Fascinating Native Bumblebees

 

Bombus sonorus- Summertime bumblebee in San Diego

While everyone is aware of, and recognizes, a common European honeybee, most people wouldn't be able to recognize a native bee. A good reason for this is because they come in a large variety of shapes and sizes, ranging from barely visible to large glossy black carpenter bees. It is very likely that a wide variety of native bees are already in your garden.

While carpenter bees fly past very visibly, most of the others zip past with little fanfare and a great deal of haste, as they have little time to waste. From the time they emerge from their cocoons the females are devoted to one thing and one thing only, the building and provisioning of their nests. The males, on the other hand, have nothing to do but mate with as many females as possible, and to fight off other males trying to do the same thing. Anything that keeps this from happening reduces their chances of passing on their genes to the next generation. They are set on maximizing their reproduction.

Tiny Halictus bee on a California Poppy                                    Photo by Don 0wens

A novel way native bees can speed things up is by "traplining". This is a remarkably clever foraging strategy that seems impossible in such a small creature as the bumblebee. Bees instinctually know to visit flowers for pollen, as nest food, and for nectar, for their own energy needs. After finding the flowers, they must prioritize them according to the floral reward each individual patch of flowers provide. In just a few trips, bumblebees will sort out the most efficient route from their circuit of flowers back to the nest. Keep in mind this keeps changing as plants go in and out of bloom. Bees are traplining when they visit flower patches in a stable and repeatable sequence. It is remarkable to me that these tiny brains can do such incredible feats.

To avoid wasting precious time bumblebees also practice "floral constancy." Meaning that they will spend more time on one species of flowers or species with similar floral characteristics or morphologies. By concentrating only on similar floral structures the process and handling is as close to the same with each flower as possible. Using this method greatly speeds up how fast bees gather pollen. Different flower species vary wildly in their floral structure and where (or if) they have pollen. You can imagine using floral constancy as a foraging strategy is a powerful tool for the bees. It also allows other bees to concentrate on other floral forms so all the available flowers are used and pollinated most efficiently. Is that cool or what?

Buzz Pollination

Possibly the most fascinating time-saving trick used by bumblebees is called "buzz-pollination" or sonication. There are approximately 24,000 species of plants in different plant families that make it difficult for bees to get the pollen. You are familiar with at least a couple of the plants if you eat potatoes and tomatoes from the Solanaceae Family. The Solanaceae Family is unique in that the pollen is hidden in poricidal anthers. Normally, the pollen from plants is prominently displayed and easily accessible to pollinators on the distal end of anthers. Bumblebees have figured out a fast and efficient way to gather the hidden pollen in poricidal anthers. Imagine a tube with holes on the ends and pollen inside. This is roughly the shape and structure of a poricidal anther. Bumblebees land on the tubular anther, bite the end, and grasp it firmly with their clawed feet. To access the pollen they disengage their flight muscles and vibrate them at a higher frequency, the force of the frequency forcibly expels the pollen, and dumps it all over the bee. When you listen to this happening in the garden the normal buzzing is interrupted by a high-pitched whine when the bee is sonicating. The magic frequency is about 270 Hz, “equivalent to a C-sharp above middle C on the piano.” Sonication allows the bumblebee to pollinate much faster than normal. 

This is a small snapshot into the wonderful world of native bumblebees, and it is by no means exhaustive. I have plenty to share. Please take care of the bees that visit the flowers in your garden. Consider planting native plants and minimizing pesticide use to increase the chances you will see more of these wondrous creatures in years to come.

Gardening for Wildlife

                                           Gardening for Wildlife

It is easy to fall in love with flowers. Once I figured out I can have flowers, birds, butterflies, lizards, and so much more I was hooked. Inviting wildlife into the garden suddenly makes gardening come alive with sound, movement, and activity. No longer just looking at flowers, but now participating in fostering growth and health - creating an ecosystem! 

Bombus vosnesenskii on Verbena lilacina                                                                  S.Reeve

Few places possess the biological richness of our home in San Diego County. In fact, San Diego is deemed a “Biological Hotspot” because of the high species richness that is unparalleled in the continental United States. One way we can help protect the large number of unique species is to landscape our homes with native plants. Think about it. Millions of years have honed the relationships between the endemic flora and fauna to the perfection that exists today. 

Sphaeralcea ambigua                                                                                            S. Reeve

Look around - what plants do you commonly see in your community? That’s right, just a small number of exotic plant species that seldom feed any wildlife exist in most gardens. The nectar from that tropical hibiscus or rosemary is not nearly as nutritious for local hummingbirds and bees as is the nectar produced by natively occurring Salvia mellifera or Phacelia campanularia. Local plants offer optimal nutrition for local fauna. Not only that, but exotic species are often poisonous to our fauna. For example, Nandina berries, although eaten by local birds, may kill them if consumed to excess. An opposite example of this is between our native Aesculus californica and honeybees--an exclusive diet of pollen and nectar from this plant will kill or disfigure the progeny of the honeybee. Honeybees are not from San Diego they originated in Europe and did not evolve to partake of our native Bottlebrush. Let’s give our local fauna the local plants that offer them the chance to thrive.

Ribes speciosum                                                                                                     S. Reeve

But, you say, my Pyracantha has fruit that the birds relish. That may be true, but recent studies show that not only is the nutrition superior in local plants, but the phenology or timing of the plants makes all the difference to the reproductive success of the creatures that evolved to eat the plants. Meaning that even though a species of bird will consume fruit from non-native plant species their reproductive fitness is decreased just enough to negatively affect the birth rate. Both the timing of the crop and the nutrition of non-natives are inferior to the native species.

So we have the excellent nutrition native plants provide, plus native endemic plants are drought tolerant. In San Diego we typically get less than a foot of rain a year, and all of it in the months of winter and spring. Native plants have evolved adaptations to be able to survive on little water in the colder months and no water in the summer. Better yet, using locally sourced native plants fine-tunes the drought tolerance to the same conditions as exist in your garden at home. That means little-to-no supplementary water, even in the summertime.

Salvia spathacea                                                                                                    S. Reeve

Here are a few things to keep in mind when seeking to attract wildlife to the garden.

1) Plant trees, if you have room, plant a native oak. There is nothing better you can do than to plant a native oak--as they support far more species of wildlife than any other plant! 

2) Plant mostly natives. I get it, is it fun to plant some non-natives. Studies show that if a garden has at least 70% natives it will help wildlife reproduction.

3) Use plants to feed hummingbirds instead of feeders. Native Salvias, Sphaeralcea, Ribes, and so many more feed hummingbirds, bees, and other insects. Keep in mind a hummingbird’s diet ideally is 80% INSECTS not nectar from a feeder. Planting plants gives a home to the insects a hummingbird and her babies depend on for good health.

4) Leave some mess in your garden. Last year’s hollow stems, will be home to this year’s baby bees. That pile of rocks or wood in the corner can house bees, lizards and more. Leave bare earth for native bees to nest in.

5) When planting, keep in mind vertical space. Species richness is always higher in gardens with trees, shrubs, and groundcovers. Gardens with only perennials are poor in richness.

6) Include a water feature accessible by wildlife

7) Keep an organic garden free from all pesticides.

A Mix of Native and Non-native Plants                                                                      S. Reeve

The biological richness of San Diego County means we have a large number of species of plants to choose from. And the great thing is these plants are gorgeous and occur nowhere else in the world! So let’s do this! Let’s plant natives, let’s bring back the waning populations of birds, butterflies, and bees. We have the power to keep San Diego biologically rich and diverse.  

Grindelia stricta var. platyphylla--Great groundcover for summer pollinating insects

Grindelia stricta var. platyphylla is a good strong dependable groundcover for Southern California Gardens. An assortment of bees, syrphid flies, moths, and butterflies find a valuable source of pollen and nectar in the attractive large yellow daisy flowers. This is a long-blooming plant in my garden. It starts blooming in early July and continues through the summer into the fall. 

    Grindelia stricta var. platyphylla                                                                                                            S. Reeve

There are three forms of Grindelia stricta and they sort by size of the phyllaries, the size and shape of the leaves, where they occur, and their habit. These are all coastal plants in the state of California. Grindelia stricta var. stricta is generally found in Northern California. Grindelia stricta var. angustifolia is found in the San Francisco Bay Area. Grindelia stricta var. platyphylla (Greene) M.A. Lane is primarily found along the southern coast and in the Channel Islands. 

Of the three, Grindelia stricta var. platyphylla, is the most garden-worthy because of its habit and appearance. This is a long-blooming plant, but it is also very attractive and dense even when not in flower. In this variety, the dark green leaves are larger and spatulate becoming more congested with smaller internodes at stem ends. This gives the plant a full habit that chokes out most weeds. 

    Grindelia stricta var. platyphylla  Leaves at stem ends                                                                           S. Reeve    

Grindelia stricta var. platyphylla  groundcover                                                                                 S. Reeve            

Grindelia stricta var. platyphylla occurs along the coast on the upper reaches of dunes, bluffs, and along road edges and in coastal sage scrub habitats in sandy soils. It does well in garden situations. Unlike many natives, this plant does best with occasional summer water to emulate the fog drip it gets naturally. It does well in full sun along the coast but looks better inland if given a little shade, or a morning sun situation. This is an easy low-maintenance plant that looks good without much work. While it prefers sandy soil it also does well in clay soil if planted high to provide better drainage. Because it is a coastal plant, it also tolerates wind and salt spray so can be useful for tricky areas in the landscape. After the plant is finished blooming in the fall, you can shear it back for a neater appearance. I have never felt the need to do this and my plants still look good. Subsequent years can find the plant base getting a little woody, and you can either chance cutting it back, and hope it regrows, or let it fill in with new growth during a new growing season.

    Grindelia stricta var. platyphylla  phyllaries                                                                                         S. Reeve

The common name of this plant is the Dune Gumplant. It is so named because of the resin or gum that the phyllaries produce before the blower bud is mature. Numerous phyllaries have a unique reflexed shape that is very interesting. The upper part of the flower bud develops a sticky pool of glistening resin that discourages herbivory. As the bud matures and starts to open the gum is no longer in evidence, and reveals the sunshine yellow flowers to garden pollinators. You can see the "gum" in the bud more clearly in the photo below. This secretion really slows down the Argentine ants which is great!

     Resinous gum in the bud of Grindelia stricta var. platyphylla                                                    Dee Warenycia

In the plants I have observed the amount of gum, and the size and shape of leaves vary. The plants I have do not make much resin. There are a couple of prostrate forms chosen for their superior garden traits. One is called 'Mendocino' and it was selected for its prostrate habit and larger flowers. The second is carried by San Marcos Growers and Suncrest and called 'Ray's Carpet'. It was selected and named for Ray Walsh who collected it in the 1980s. It was introduced by Santa Barbara Botanic Garden. My plants are from Las Pilitas Nursery and are not selections but they are still very pleasing and garden-worthy.

I grow this plant primarily for the large number and assortment of pollinators it attracts. It is one of the best plants for pollinators because the large ray-and-disk flowers provide a large landing platform for so many insects, even comparatively large, bumblebees use this plant. Many bee genera visit this plant including Halictids, Megachilids, Melissodes, honey bees, and Bombus. Several species of butterflies and skippers are attracted to this plant, including the small butterflies,  Painted lady (Vanessa cardui), American painted lady (Vanessa virginiensis), West Coast lady (Vanessa annabella), Buckeye (Junonia coenia), and it is also a favorite of the Great Copper (Lycaena xanthoides). Moths nectar on it at night including Orange Tortrix (Argyrotaenia Franciscana), Oidaematophorus occidentalis, and Cremastobombycia grindeliella. The long bloom time makes it dependable for pollinators too. 

The plant tends to spread widely by rooting at internodes or by infrequent seeding. I have picked up individual stems and followed them back and I didn't notice much rooting. In my garden, the plant just seems to grow outward at a steady rate. It is easy to keep it smaller if you want. Larger patches make it more visible for bees so keeping it at least a square meter in size is best. I haven't noticed it spreading by seed, it is possible it does, but it is well-behaved. One of the patches I have is about four feet by five feet in maybe six years. I hope to find rooted stems so I can move it to other locations. 

    Patch of Grindelia stricta var. platyphylla                                                                            Flickr

Presently, it is blooming next to Salvia clevelandii 'Winifred Gilman', Iris douglasiana, and Scrophularia californica. I would like to try it in a large sunny area with other low-growing natives and non-natives that tolerate a little summer water in a quasi-meadow situation. I would like to mix it with Gaillardia, native Iris, Sidalcea, Erigeron glaucus, Zauschneria 'Everett's Choice', low-growing  Salvia, Eriogonum grande-rubescens, Penstemon 'Margarita Bop', Senecio palmeri 'Silver and Gold', Lessingia filaginafolia 'Silver Carpet', and native clumping grasses. This plant can also be grown as a "spiller" over a low wall. If you have deer, they don't particularly like this plant because the leaves are rather coarse and can be sharply toothed. 

I wouldn't be without this plant as it is one of the best plants for pollinators in the summer. Grindelia stricta platyphylla is a beautiful, low maintenance, and drought-tolerant plant perfect for your native wildlife garden. 

Deceptively Delicate: Eriogonum grande-rubescens

California native plants often surprise me. Eriogonum grande var. rubescens looks so delicate and cute, but it is is a solid performer in the garden. It is far from delicate. I remember when I first saw it and thought, "what a flimsy little plant", and I wondered how many plants would it take to form a nice display? It didn't seem possible that a plant with such a dainty flower could ever amount to much. I was wrong.

photo by Pete Veilleux, East Bay Wilds

Such a big name for such a petite plant! Eriogonum grande rubescens, after much research the origin of the name, "grande" remains a mystery to me. The peduncles of the species Eriogonum grande can reach 3-5 feet and were, indeed, "grande", but not so with this petite variety. The blooming flowers of a large number of Eriogonum grande var rubescens is impressive so I will call that "grande" instead! 

This plant is native to the three of the Channel Islands, San Miguel, Santa Cruz, and Santa Rosa. It blooms for a long time, starting at the end of May, in my garden, and through the summer and into the fall. The books say full sun, but I have quite a few in dappled shade and they are doing fine, although, they are not as floriferous as the plants in full sun. It does tend to seed into the sunnier areas. I have it in sandy loam, but it seems tolerant of a wide range of conditions, as it also grew well in full sun in a dg path. I have read it tolerates clay as well as long as it drains. It likes well-drained soil on the drier side, but it doesn't die off like some CA natives with summer water. On the other hand, once established, it can survive without additional water. Like I mentioned, this is a deceptively tough plant! 

       Eriogonum grande var. rubescens                                                                                    S. Reeve

If the buckwheat is happy it will reseed and carpet the area with a weed-suppressing amount of baby plants. These all form basal foliage through the winter and early spring. The plant itself is about a foot across and two feet tall when it blooms. The whitish leaf petioles originate in the center of the plant and end in roundish or oval deep green to slightly teal-colored leaves with wavy margins. The green upper leaves become progressively greyer as the dry season goes on. The undersides of the leaves are startlingly white and tomentose. As this plant is naturally found on seaside cliffs I imagine this indumentum keeps the ocean winds from dehydrating the plant, and the white color helps the plant reflect sunlight bouncing off of the rocks.  As an ecologist, I wonder if fog drip from the shiny top of the leaf is collected by the downy hairs underneath to help with hydrating the plant? 

    Eriogonum grande var. rubescens                                                                                                      S. Reeve

Around May they send up a curiously inflated, perfectly round, naked stem, that branches almost perpendicular to the stem, and rather violently too, with the flowers as far away from each other as possible. The stem forks and divides into three (flower stems erect, trichotomously branched) or four branches and divides further into smaller stems before flowering at the ends of branches. To my eye, this is a really odd arrangement. No doubt there is an ecological purpose for this. Maybe it is a particularly strong construction for such a windy area? 

   Eriogonum grande var. rubescens                                                                                                      S. Reeve

Small pom-pom flowers in varying shades of the palest pink-to-red bloom on the branched stems can bloom for several months. The terminal flowers are only about an inch across but pack a visual punch when massed. Although the tiny pink sepals of the lobed calyx look delicate, but they remain colorful for a long time. The color of the flower varies so much that it might be a good idea to shop for this plant when it is blooming to get the best shade for your garden. 

                                                        photo by Pete Veilleux, East Bay Wilds

If you garden for wildlife in California, Eriogonum species are some of the best plants for a wide array of native organisms. The small, easy to land on flowers, work for tiny insects and even larger bees, ants, syrphid flies, bee flies, wasps, butterflies, moths, and beetles. Butterflies that use this plant include Common Buckeye, Acmon Blue, Gray Hairstreak, Large White Skipper, Mournful Duskywing, Common Checkered Skipper. Moths use this plant too and include Brown Arches, Buckwheat Borer, and White-lined Sphinx. Acmon Blue uses the plant as a host plant as well as for nectar. Below is the larva of the common Gray Hairstreak butterfly consuming Eriogonum grande-rubescens as a host plant. The redder the flowers the pinker the larvae. Grasshoppers, beetles, and moth larvae consume all parts of this plant, including the roots. It really is remarkable how well utilized this plant is. Of course, birds and lizards will also be plentiful because of the wealth of insects on it, and for the little seeds.

       Gray Hairstreak larva                                                                          photo by Michael Schmidt 

      Eriogonum grande var. rubescens                                                                                                      S. Reeve

After a couple of years the plants seem to come out of the ground and will either die or you can cut them back. They don't seem to be long-lived but are readily replaced by seedlings. Try to leave the seedheads on if you want to feed the seed-eating birds. To keep it from seeding in the garden, cut off the flower at the base of the stem after the flower color fades. I don't do any maintenance on mine and let them spread. Deadheading the flowers before they form seeds will keep them blooming longer. They will not spread into areas where plants already exist. If you have them along a path they will spread further along the path as that is the available free space. You will also find them in the path, but they are easily pulled or given away. This plant is hardy to about 15 degrees F. I do not fertilize my plants, but I do mulch them. As you can see I have California poppies in with this plant and I like that because once the poppies are done the Eriogonum takes over. You will want to put this demure pretty native where you can see it and where you can see the nature that it brings.

Romneya x 'White Cloud'

Amazing photograph of Romneya coulteri by Aaron Landworth

Romneya x 'White Cloud' flower                                                                                                S. Reeve

Romneya coulteri may be the most iconic native California flower. Indeed, author of the book, The Wild Flowers of California, 1897, Mary Elizabeth Parsons, deemed it the, "Queen of California Flowers." I remember the first time I saw it, it was planted en masse along the side of the road in a hot and dry location. I started hyperventilating at the sheer spectacle of so many mammoth luminous crepey-petalled white flowers with a large boss of bright orange-yellow stamens. The easy access to so much pollen had sent the honey bees into a frenzy and flowers had a crowd of honeybees in each one. Ever since then I have wanted to grow this plant. The memory of it caused me to make it one of the first plants I put in the ground at my home in La Mesa, CA. Nothing teaches you more about a plant then growing it and I have learned so much since then. When it is blooming it is easy to see why it is called the, "fried egg" plant. It is also referred to as the Matilija Poppy as it is native to Matilija Canyon in the Ojai Valley and named after Chief Matilija of the Chumash tribe. Although well known by the native Indians, this plant was collected by Irish botanist Dr. Thomas Coulter in 1833, and the genus name came from his friend, astronomer, Dr. Thomas Romney Robinson.

There are two species in the Genus, Romneya coulteri and Romneya trichocalyx. These are Southern California natives with the range of Romneya trichocalyx extending into Baja, CA. Romneya trichocalyx is commonly called, "Hairy Matilija Poppy." It differs from Romneya coulteri in that it can be found at higher elevations, blooms for a shorter period of time, has smooth light brown seeds, and bristles on the sepals and stems. It is also smaller in stature and the leaves tend to be finer and narrower. Romneya coulteri has furry seed pods but has no prickles on the stems or leaves. 

Romneya coulteri reaches 8 feet or taller in my garden and the plant spreads widely and invasively by runners. These suckers or traveling roots are impressive in their size and scale. They are golden yellow and up to a half-inch in diameter, and they can vigorously travel for many feet before they pop up again. As boisterous as the roots are, you would think they would transplant easily, but this plant is particularly sensitive to having its roots disturbed. I have tried a number of times to share this plant with others, and even with the most healthy and sizeable rooted sections, it fails. 

Flowers of Romneya coulteri are up to 7-or more inches across and are said to be the largest flower of any native California plant. The buds are round and hold so much promise of gigantic flowers to come. The flower has 5-6 large crinkled white petals and is fragrant.

    Romney x 'White Cloud'                                                                                                                S. Reeve

Bristly Sepals of Romneya x 'White Cloud'                                                                                        S. Reeve

After growing both the straight species of Romneya coulteri and the cross between R. Coulteri and R. trichocalyx called, 'White Cloud', I much prefer the cultivar because it stays more compact, is not as inclined to travel, and has even larger flowers. Since it is a cultivated selection it must be propagated vegetatively, and root cuttings are commonly used. The key is to take them in the winter. The two species hybridize readily leading to Theodore Payne noticing the special qualities of one such hybrid in 1940, and naming it 'White Cloud'. The plant was almost lost until Tree of Life Nursery brought it back into cultivation in the '70s, and that is where I found it for my own garden.

     Romneya x 'White Cloud'                                                                                                         S. Reeve

Romneya x 'White Cloud' also has lovely bluish foliage that is the perfect color to complement the colors of the flower. I have noticed Romneya coulteri can have more greenish colored foliage, and I prefer the blue hues of 'White Cloud'.

     Romneya x 'White Cloud'                                                                                             S. Reeve

This plant blooms for over a month in the late spring. I garden for wildlife, and this plant is no exception to my other wildlife-attracting plants. Honey bees often crowd the flowers and the bees jostle each other vying for a larger share of the pollen. I have not noticed native bees on this plant, but it could be only the smaller native bees visit. 

    Romneya and honey bee.

One of the decidedly large drawbacks to the species Romneya coulteri is the exuberance with which it spreads. In one place I have it I continually have to pull out runners. You can slow these down by never watering this plant. It is tricky to get established, but once it figures out it likes where it is, stand back, and watch out! The second time I planted it was a much more appropriate place where it could spread to its heart's content. Luckily, if you don't have space, it can grow well in a pot. This plant likes hot dry sandy soil areas with good drainage and full sun. Plant it but disturb the roots as little as possible. You will know within a day-or-two whether the plant will take or not. This plant will decide right away if it will thrive or die. You may have to try it in a few different locations before it will settle in. Where I have a little shade, Romney coulteri can get rust on it after it flowers. Because of this I cut it down to the ground after it flowers. It comes back just fine. The furry brown oval seed pods contain many tiny golden seeds that germinate easily after a fire. The football-shaped seed pod peels open at the top when the seeds are ripe and looks very much like a miniature tiki torch. Native plant nurseries get good results from smoking pine needles for several minutes above sown flats of seeds. This plant is hardy in Zone 7-10 and goes dormant in the winter. 

     Seed Capsules of Romneya x 'White Cloud'                                                                                  S. Reeve

Great Little Tree

If you are looking for a great fast-growing little tree that blooms in the heat of the summer try Malacothamnus densiflorus. In my garden, this plant has reached eight feet tall and 5 feet wide in about two years. Here it is July 4th and it has been blooming now for about month and still going strong. Given a little water, this plant can rebloom later in the year. The pretty rose-pink bowl-shaped flowers are held on long beautiful wands at the ends of the branches. Flowers occur in congested or glomerate clusters of ten-or-more flowers at nodes in long panicles that bloom for an extended period of time, hence the name "densiflorus." The flowers have a fused five-lobed calyx and fused base five-petalled flowers. The stamens are also fused into a tube. They can bloom from May into July, with some scattered blooms later in the season. Palmately veined coarse leaves are gray-green and have 3-5 lobes. Leaves and stems are covered in hairs with the underneath part (abaxial) being especially hairy, with some stellate (star-shaped) hairs. 

Malacothamnus densiflorus flower panicle                                            S. Reeve

This California native occurs South of Los Angeles down into Northern Baja California on low elevation recently burned chaparral slopes and nearby coastal sage scrub. Most literature calls this a shrub, but given today's smaller landscapes, it is also an ideal small tree. Limb it up to make it more tree-like. Some accounts say it can reach 15 feet tall and 10 feet wide. The Jepson Manual says six feet tall. 

Notice the many-flowered nodes, here with spent flowers                                         S. Reeve

The tree has a pleasing weeping appearance when it is bearing the weight of the flower panicles.  This is a low water use plant. I barely water it and it grew this large in two years. Almost lost this plant to gophers at one point as they ate many of the roots. In spite of the hairy leaves that normally make a plant less palatable to herbivores, Malacothamnus is a deer and rabbit favorite. 

Weeping panicles of flowers at terminal ends of branches                                                                S. Reeve

As many of you probably know, I garden primarily for wildlife. My garden is full of plants with high wildlife value, and this one is no exception. White Checkered Skippers and West Coast Lady butterflies use Malacothamnus as a host plant. Additional butterfly species nectar on the flowers. Native ground-nesting bees in the Genus Diadasia favor this plant and males can be found sleeping in the flowers at night. Bowl-shaped petals hide the bee and also make it very convenient for the boys to find eligible females in the morning. Diadasia species are very cute little furry bees that specialize in Malvaceae. Female Diadasia are important pollinators of this plant and carry the pollen back to the nest on the long hairs of their hind legs. Look for them visiting Sphaeralcea flowers too. 

Diadasia species in the flower of Malacothamnus fremontii  Photo by Hartmut Wisch

Other wildlife use this plant too. Anna's hummingbirds are known to pick insects out of the open blooms. Bushtits and other birds eat the seeds in the fall. Ground squirrels also eat the seeds.

Close-up shot of a flower                                                                                                                     S. Reeve

To grow this plant well it needs well-draining sandy loam soil. It can grow in clay if it on a slope or otherwise well-drained. A slightly acidic to slightly alkaline soil pH is best. Malacothamnus is drought tolerant and heat tolerant. Root systems of these plants are wide-spreading and make them well-suited to secure a hillside. Unfortunately, the plant is not long-lived, which seems to be the case with most fast-growing shrubs and trees. Don't be afraid to prune as much as you need to maintain a good form or denser branching. 

Closeup of the leaf and flower                                                                                 S. Reeve

From what I have read, this plant can sucker to form a thicket, yet I have not seen this in my garden. You can dig up suckers and replant elsewhere. I have definitely seen another species, Malacothamnus jonesii, sucker. I think if I watered more I would see more suckering, but I have not. I had Malacothamnus jonesii for several years and it mysteriously and suddenly died. It was a beautiful silver-foliaged plant. Luckily, it put out a couple of suckers before it was no more. I have a sneaking suspicion that my summer watering killed it, as it has killed other natives in the past before I figured out I shouldn't water some of my natives in the summer. It can withstand cold temperatures down to 10-20 degrees F. If you enjoy watching the wildlife that plants can bring you should try growing Malacothamnus densiflorus.