One great plant that's often overlooked as a choice for the bee garden is flannel bush -- also referred to as California fremontia -- (Fremontodendron californicum). While the species is sometimes available, you're more likely to find one of the cultivars. Look for this plant at specialty nurseries or well-stocked independent garden centers. The species and its cultivars 'California Glory', 'Pacific Sunset', and 'San Gabriel' are quite large, reaching up to 20 feet in height. The cultivar 'Ken Taylor' is more manageable for a small garden; 'Ken' will reach up to six feet tall and 10 feet wide but can be kept smaller with pruning.
Here's why flannel bush makes a great choice for the California (Sunset zones 4-24) bee garden:
1. It's an attractive, eye-catching plant. The large, 3-inch wide flowers cover this plant at peak bloom. You may have noticed large plants along California highways that are covered in yellow flowers come springtime. That's flannel bush...from California Native Plants for the Garden: "A California fremontia in full bloom is an unforgettable sight." This plant was photographed at the Old City Cemetery in Sacramento.
2. Going low water? Flannel bush needs NO summer water, in fact summer water is HARMFUL to this plant. Like many of our California natives, it evolved in hot, dry areas in the absence of the root diseases that are favored by warm, wet conditions. It thus has no defenses against these diseases.
3. Fast growing. Flannel bush grows quickly; you'll have lots of bloom by the second year after planting. This also makes it a good candidate for an espalier. The best cultivars for this are 'California Glory' and 'San Gabriel'. This photo of 'Ken Taylor' was taken one year after planting, at which point is was already about 4 feet across. This cultivar, which is a cross of the Sierra foothills species Fremontodendron californicum decumbens and 'California Glory', has a prostrate form that looks nice on a bank orberm. This is also a great way to provide the excellent drainage this plant needs. Another small (3 feet tall by 6 feet wide) flannel bush is 'Dara's Choice', which was introduced by the Santa Barbara Botanic Garden. It is a cross between Fremontodendron californicum decumbens and Fremontodendron mexicanum.
4. Fun fact for plant nerds....flannel bush nectar fluoresces blue under UV light. Amaze your friends and family with this neat trick! This was first observed by UCD Entomology's own Robbin Thorp many years ago (Thorp, RW et al. 1975. Science (189): 476-478). This property has been observed in many plant nectars and is thought to provide a visual cue to foraging bees (remember that bees see in the UV spectrum).
5. Flannel bush nectar is nutritious. It is rich in isoflavenoids, which may have antimicrobial properties helpful to bees (Scogin, R. 1979. Bot. Gazette (140): 29-31).
We have Fremontodendron californicum and the hybrid 'Ken Taylor' at the Haven. There are also several nice specimens at the UC Davis Arboretum. This plant is at its best in early spring. One note of caution: some people are irritated by the small hairs that cover its leaves. Plan on wearing gloves and long sleeves when pruning.
We know it's fall at the Honey Bee Haven is when our asters come into their full glory. This large (more than 600 species) group of plants even has its own book. Asters recently underwent a taxonomic revision that split the genus Aster into five genera. The commonly-available species either remained in Aster (Old World species) or were moved to Symphyotrichum (New World species).But the common name aster still applies to all. True plant nerds will want to read this detailed summary of the cultivated species. Blooming into November, asters are a valuable late-season source of pollen for bees and nectar for bees and butterflies.
These are the species we have at the Haven, listed in order of bloom:
Aster 'Purple Dome': Symphyotrichum novae-angliae 'Purple Dome'. The species is native to the US east of the Rocky Mountains. This cultivar, which is a UC Davis Arboretum All-Star, is the first aster to bloom at the Haven. It typically starts flowering in late June; deadheading results in several more flushes of bloom until frost. It produces deep purple flowers and stays under 18 inches tall. It will spread and we divide ours every other year.
California aster: Symphyotrichum chilense. This one is about 24 to 30 inches tall; the amount of spread depends on how frequently it is watered. Ours receive a deep soaking about every three weeks and so far we've not seen any invasive tendencies.
Aster 'Wood's Pink':Symphyotrichum dumosum 'Wood's Pink'. This aster has bright pink flowers and is native to the northeastern US. Ours is watered daily. It grows 12-16" tall, making it a nice addition to the front of a border. The species was used as a parent for developing smaller cultivars by Victor Vokes of the UK War Graves Commission, who needed low-growing, late fall color for WWI cemeteries.
Aster 'Fanny's': Symphyotrichum oblongifolium 'Fanny's'. The story of this cultivar of a southeastern US species is that Ruth Knopf of South Carolina acquired the aster from her maid, Fanny, who in turn received it from her grandmother. Fanny is 3 to 4 feet tall and wide.
Manzanitas (Arctostaphylos spp.) are a diverse group of California native plants that serve as a great winter resource for bees, especially native bees that fly early such as Osmia spp. and Bombus melanopygus. They are shrubs (mostly) and groundcovers (a few) that should be used in more California gardens. The waxy green leaves, peeling bark, smooth reddish to mahogany branches, and upright leaves are attractive throughout the year. These plants have stomates on both sides of the leaf so leaves are held perpendicular to the ground, rather than parallel, to minimize sun exposure and water loss. Some begin flowering in late fall, while most flower in January and February. In my own garden these held up well to drought this summer without any supplemental watering.
The California Native Plant Society has a nice article on this group; I also use the websites of Las Pilitas Nursery and California Flora Nursery to learn about new species for inclusion in the Honey Bee Haven.
According to California Bees and Blooms, two of the best for bees are the Arctostaphylos densiflora cultivars 'Sentinel' and 'Howard McMinn'. These two are also among the easiest to grow and fastest to reach mature size; the former tends to be upright while 'Howard McMinn' tends to be more rounded in shape. It is also the most adaptable; this UC Davis Arboretum All-Star can tolerate heavier soils than most manzanitas as well as some summer irrigation. Two other great cultivars for gardens are 'Austin Griffiths' and 'Sunset'.
Manzanitas host a gall aphid, Tamalia coweni. The aphid lays eggs in manzanita leaves and hormones secreted by the developing aphid induce formation of a gall on the leaves. Cut these open to view the developing aphids inside; they are not considered to be a plant pest.