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.
While most folks don't want to have to search down plants for their garden, some of us avid gardeners love the chase. Here are profiles of some great bee plants that, despite being easy to grow in most of California, can be difficult to find for sale. To add these to your garden you'll likely need to track down a specialty nursery or an arboretum or native plant society sale, or luck out at your favorite garden center. I've listed them in order of bloom.
Butterfly rose, Rosa x odorata 'Mutabilis'. There are few roses that we recommend for bee gardens; most garden roses have flowers with excessive petals and scent that are produced at the expense of pollen and nectar resources. In addition to our native California rose, this Asian native and UC Davis Arboretum All-Star is a good choice for the bee garden. Needing only a deep soaking every two weeks in our area, its only downside is that it can grow quite large and may need summer pruning to keep it in check. Flowers are present nearly year-round and open as yellow but change color to pink and then red as they age. This colorful combination pairs nicely with other bee plants such as the yarrow and hummingbird mint shown here. At the Haven it is used primarily by honey bees. It provides nectar and pollen.
Tall sunflower 'Shiela's Sunshine, Helianthus giganteus 'Shiela's Sunshine'. This eastern US native will grow throughout California and makes a striking addition to the bee garden. All sunflowers are valued for their long bloom time, which generally extends from mid-summer into fall, and the fact that they provide both pollen and nectar. 'Shiela' can reach up to 8 feet in height with sturdy stems that don't need staking. Naturally occurring in moist areas, it will need at least weekly watering in central California; at the Haven we grow it in a container where it's watered daily. Look for honey bees, sweat bees, and longhorned bees to use it.
Asters. California aster, Symphyotrichum chilense, and aster 'Bill's Big Blue', Symphyotrichum 'Bill's Big Blue'. The asters (New World species were recently moved from the genus Aster to Symphyotrichum) are a great late-season pollen and nectar source and a staple of the bee garden because they bloom when little else is in flower. With the exception of our native California aster, these plants need ample water, typically about once per week. California aster cultivars 'Purple Haze' and 'Point Saint George' have deeper purple flowers and tend to be more attractive to bees than the species. The non-native asters are from various regions in eastern North America, depending on species (of which there are about 600; they have their own book). Asters are used by honey bees, leafcutter bees, and sweat bees. Of the non-native species, we especially like 'Bill's Big Blue' at the Haven. Measuring about 6 feet tall and wide, it blooms continuously through October and November. Asters will grow in all of California; the native species does well everywhere except the desert and high mountains.
Ask most folks about "fall color" and they'll picture trees turning shades of red, orange, and yellow. Here at the Haven, on the other hand, we think about all the plants that will bloom until frost. These provide honey bees with critical late-season honey-making resources; other bees and butterflies use these late bloomers as well.
I wrote about fall planting a few weeks ago. Here are some recent photos from the garden showing our version of "fall color."
Although they still go by the common name of aster, the New World plants in this group are now in the genus Symphyotrichum. Here's one of the largest, Symphyotrichum 'Bill's Big Blue' with many honey bees working its flowers. 'Bill' is a big guy, so be sure to give him plenty of room to spread and sprawl.
Pretty, easy-to-grow, and great for bees. What more could you want in a flower? We sow zinnia seeds directly into the garden. Do this in May for summer bloom and again in August for blooms that will go until frost.