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. 

Tetraneuris acaulis - ever-blooming heat lover

Hymenoxys acaulis is now recognized as Tetraneuris acaulis or Angelita Daisy. "Acaulis" refers to the fact that this plant has no stem. Flowers arise directly out of a base of needle-like thin leaves. Flowering stems have no leaves, just a thin stalk with a golden daisy on top waving in the wind. The stalk of this member of the Asteraceae Family is about 12 inches tall. The grassy base of foliage gradually increases in width as it grows. This plant blooms year-around with these cheerful yellow daisy flowers that are popular with pollinating insects. Photo below of a fly nectaring on a flower. The flowers are flat and dense and easy for the tiniest pollinator to land on and feed. The bright golden yellow flowers are visible for a long distance. I really like this plant because it is so easy and gives so much back. The flowers are non-stop and it really loves heat, but not too much heat. Extended periods of 100 degree days can shorten the life of this native plant. It is hardy down to zero degrees Fahrenheit. It is very drought tolerant but appreciates a little water occasionally. 

Tetraneuris acaulis bloom with fly                                                                                                      S. Reeve

Tetraneuris acaulis                                                                                                                                 S. Reeve

This plant can really cover itself with blooms. After the flower fades the stalk is left. To neaten it up deadhead the spent stalks when they become numerous and noticeable. 

This plant is native to the western half of the US with the exception of Oregon and Washington. Depending on the location, there are 5 highly variable subspecies of this plant. California and the Southwest is home to Tetraneuris acaulis var. arizonica (Tetraneuris acaulis (Pursh) Greene var. arizonica (Greene) K.F. Parker). This plant is found at 1300-2900m in grasslands and hillsides. The California population is found in and around the Mojave National Preserve. I am always fascinated by the adaptations a plant makes for its environment. In this case, compared to Tetraneuris acaulis, Tetraneuris acaulis var. arizonica is stockier and covered in downy hairs and the foliage appears silvery-gray rather than green. The flowers and foliage are more substantial and fleshy. Increased sunshine and less precipitation make this version better adapted to life in the Southwest. 

Photo ©Al Schneider, http://www.swcoloradowildflowers.com

As is the case for so many Southwestern natives, this plant must have good drainage to survive. It becomes susceptible to fungal infection if drainage is less-than-ideal. The literature says this a short-lived perennial. I haven't grown it long enough to know if this is true, although, it seems that perennials that bloom constantly poop out faster than plants that don't. 

Angelita Daisy combines well with other plants. As an example, here is Eremophila hygrophana with another desert daisy, Baileya multiradiata, but this could easily be Tetraneuris acaulis. You can also combine it with smaller Leucophyllum selections, Salvia greggii, Agastaches, Eremophila maculata 'Valentine', native Calliandras, Hesperaloe parviflora etc. It would also be nice to plant a mass of this plant. It is rabbit resistant. 

Eremophila hygrophana and Baileya multiradiata                              S. Reeve

Small but Important

Croton setiger                                                                                                                            S. Reeve

You have probably seen this plant while hiking, or possibly while driving since it likes to grow in road cuts and disturbed areas. Even if you saw it, you may not have even noticed it since it blends with the landscape and has a really low profile. The plant has the peculiar name of Croton setiger or Dove Weed. This annual grows mainly all through California and into Western Oregon and Washington, and down into Baja. In San Diego, we are at the bottom of its range, as it needs, at minimum, 9 inches of rain a year. This plant grows at low elevations but can be seen up to around 2500 feet above sea level. It can be found in dry soils in CSS, oak woodland, and in grassland habitats. It blooms for a long period of time from spring into fall. Not that you would notice because the flowers are tiny, about an eighth of an inch and they blend into the foliage. The foliage has a lemony chemical smell.

Croton setiger Doveweed                                                                                                  S. Reeve

Why I love it and why I noticed it, is when you get down and look at the flowers they are covered in tiny native pollinators like this blue wasp. This wasp is probably a Spider Wasp or Aporus luxus. This was the best photo I could get with a cell phone. I kind of cut his head off in the picture. What a startling blue! I could have spent all afternoon watching the little pollinators scrambling around on the tiny flowers. It looks like flowers presented on white dinner plates. 

                  Blue wasp (Aporus luxus) on Croton setiger                                                          S. Reeve   

Ron Vanderhoff 

From what I could find the flowers offer pollen in the male flowers presented at the branch tips, and are very accessible to tiny pollinators looking for lunch. Male flowers have no petals but have sepals and stamens. Female flowers are in the axils. The female flowers have no petal or sepals and are just a single swollen ovary with a style sticking up. Not sure how this very unenticing flower gets pollinated? Turns out the beetles probably do it. They are not efficient pollinators, so when they are bumbling around on the male flowers there is plenty of pollen that drops into the female flowers lower down on the plant. Thank you to the Natural History biologists at UCI for the great macro photography, especially to Ron Vanderhoff, so I could understand the flower structure. http://nathistoc.bio.uci.edu/plants/Euphorbiaceae/Croton%20setigerus.htm

                                                                                 

This plant is entirely covered in irritating dense hairs, except for the seeds, and chemically defended against herbivory, but it gives its non-toxic seeds away freely. It is in the Euphorbiaceae and the leaves are toxic and were used as a fish poison to stupefy fish by local Indians. They are a favorite food of birds that forage on the ground like quail and doves. Nutritious seeds are about an eighth of an inch long and can be either speckled or unmottled gray. This may be a reproduction strategy so that some seeds are not recognized as food and go on to germinate. Notice the unmottled seed in the upper left.

J. O'Brien 2007

You can find seed to start this plant. It would seem to me to combine well with spring wildflowers like California poppies and others. The plant forms a low-growing mound less than a foot high and can spread up to 3 feet wide. It is just beautiful to see the neat silvery soft mounds of foliage. I wonder if any nursery has tried to grow this as a retail plant? Anyway, I love it for its silver color, neat habit and popularity with pollinators. Look for it on your next hike. 

Join me for a talk on bulbs especially suited for San Diego gardens on Saturday, March 17th at 9 am

Join me for a talk on bulbs especially suited for San Diego gardens on Saturday, March 17th at 9 am http://www.mastergardenersd.org/seminar/