FLIMBY: Know your coreopsis from your bidens

This is another installment in our Flowers in My Back Yard series, dedicated to blooming plants.

Coreopsis is the same as tickseed, but not the same as bidens, which sometimes is called stickseed.

And that right there is a great example of how people get confused about plants. The common names are all over the place -- and sometimes depend on the place where you live.

Coreopsis and bidens are terrific plants for Sacramento-area gardens. They both sport daisy-like flowers, bloom profusely, attract pollinators and tolerate low-water conditions.

They also both belong to the Asteraceae (sunflower) family of plants.

But coreopsis usually (but not always) is a perennial, while bidens typically is grown as an annual.  May is probably the last chance until autumn to get these in the ground, but into summer they can be planted in a container with other low-water flowers. (They will still need more water than in-ground plants.)

Coreopsis, aka tickseed

Coreopsis is native to North, Central and South America, with several varieties native to California. Coreopsis californica var. california is one of those.

The plant prefers a sunny spot, well-drained soil and good air circulation. When transplanting, leave 12 inches between plants -- coreopsis typically grows to 12 inches wide and 12 to 18 inches tall. It does not like to be crowded.

Most coreopsis plants bloom yellow-gold, but there are pink, red, orange, caramel and bicolor bloomers, too. The petals usually are flat, but the 'Jethro Tull' variety has fluted petals on its flowers, which except for the gold color could be mistaken for fluted cosmos blooms (cosmos also being part of the Asteraceae family).

The easiest way to deadhead the long thin stems is with shears or small loppers.

Bidens, aka stickseed, bur marigold, common beggarticks, shepherd's needles, Spanish needles, etc.

The bidens variety known as bur marigold (Bidens laevis) is a California native, typically found in wetlands, including estuaries and riverbanks. But most cultivars have been bred to avoid the sticky seed that inspired many of its common names.

Typically yellow, bidens also can be found in pink, orange and bicolor; all flower abundantly. They too like at least 6 hours of sun, are heat tolerant and can be grown in pots. 

The more compact bidens plants are less likely to need deadheading than coreopsis, but pruning does produce bushier growth. The cultivars tend to be annuals or short-lived perennials, but will produce prolific flowers into fall.

Intrigued? Varieties of bidens and coreopsis are available at the upcoming spring clearance sale of the UC Davis Arboretum Teaching Nursery. The sale is Saturday, May 16, from 9 a.m. to 1 p.m., open to the public.

Bidens 'Popstar' can be found in 3-inch pots at Bench B7. The compact Coreopsis auriculata 'Nana' and Coreopsis grandiflora 'Solar Mellow' (a somewhat larger cultivar) also are available in 3-inch pots, also at Bench B7.