Coreopsis ‘Zagreb’ is a dependable, drought-tolerant perennial in my front yard garden. I bought a couple of tiny plants at a native plant sale a few years ago because my first house had them in the garden. They have since spread into a decent little sunny swath of yellow, surrounded by lavender, catmint, and black-eyed Susans. I’ve since discovered many varieties of coreopsis—‘Solar Dance’ is in my list of favourite yellow perennial flowers.
The word Coreopsis is derived from the Greek language. Koris means bedbug and opsis means appearance, which is funny because the plant is also referred to as tickseed because the seeds resemble ticks. I’m not sure what’s worse, ticks or bedbugs, but the flowers themselves are cheery additions to any garden. And there are several varieties to choose from, some are perennials and some are annuals. Plants are generally hardy between USDA zones 5 and 9, but some are hardy down to zones 3 and 4.
Coreopsis, with its daisy-like appearance, is a member of the large Asteraceae family (which also includes cosmos, marigolds, asters and mums). The plant is native to parts of the U.S. and Canada and is a mainstay in many gardens. The National Garden Bureau even chose it recently for its annual Year Of program: 2018 was The Year of The Coreopsis.
Caring for tickseed plants
I bought my Coreopsis as small plants, but you can also grow plants from seed. They are hardy and pretty low-maintenance, though plants do look more attractive when you deadhead the spent blooms, which takes a bit of snipping here and there. You can also cut down plants to a half or third of their height after they’ve bloomed in the summer for another flush of blooms in the fall. Leaving the seedheads (rather than cleaning up the garden in the fall) will help feed the birds over the winter months.
Avoid over-watering your plants as they can be susceptible to downy and powdery mildew.
Growing Coreopsis ‘Zagreb’ from seed
You can direct-sow Coreopsis seeds once the soil has warmed up in the spring or get a head start indoors. Sow seeds about six to eight weeks before your frost-free date. Keep the soil moist and warm (about 70°F to 75°F). Once the seedlings grow, give them plenty of light. Transfer young plants to the garden once all threat of frost has passed.
Where to plant Coreopsis ‘Zagreb’
The area of my garden where my Coreopsis have spread doesn’t have the best soil—though I’m working at amending it—but it doesn’t seem to mind. Generally plants appreciate a well-drained soil. Plants bloom throughout the summer months in full sun, attracting birds, bees, and butterflies. I don’t have a problem with deer, but plants are supposed to deer resistant.
Coreopsis are perfect plants for cottage gardens, urban meadows, or wildflower gardens. The foliage typically fills in nicely and showcases prolific blooms. My plants are about 18 inches tall, so they were placed behind some of the lower-growing perennials in my garden.
Each year seems to bring new introductions to the market. Much work has been done over the years to hybridize the plants for better disease resistance, better flowers, and longer bloom times. I got to see a few interesting Coreopsis varieties when I went to the California Spring Trials in 2017. And I’ve been dazzled by others at my local garden centres.
Here are a few interesting tickseeds that are worth checking out.
Coreopsis ‘Zagreb’ falls under the threadleaf coreopsis (Coreopsis verticillata) species. It can survive in poor, sandy, and rocky soils (which explains why mine has done so well). Plants can spread both via rhizomes and by dropping seed. Mine has filled in a nice area, but at this point I want need to keep it contained so it doesn’t edge out other plants. Flowers are pure yellow and I really like the feathery foliage (hence the common name of threadleaf). It reminds me of dill, but thicker. Coreopsis ‘Moonbeam’ is another popular threadleaf variety.
Coreopsis ‘Route 66’
Part of the Cruizin’ series, ‘Route 66’ is another threadleaf variety that I encountered at the California Spring Trials. ‘Route 66’ looks like someone tried to take a red or burgundy crayon to colour over the yellow. Consequently, plants add a touch of drama to the garden and all of them look different. They are tolerant to road salt, though if you’d like to keep them out of harm’s way, ‘Route 66’ would also look pretty stunning in a container.
Coreopsis ‘Star Cluster’
Part of the Big Bang series, ‘Star Cluster’ was bred by plant breeder Darrell Probst, who has been working on breeding cultivars that are disease resistant and bloom longer. I love the delicate cream colour with hints of fuchsia around the centre. This is a long-blooming variety that flowers through the fall. It’s hardy down to USDA zone 4.
Coreopsis ‘Solar Dance’
It seems as though modern Coreopsis varieties are named after the cosmos. ‘Solar Dance’ features double and semi-double flowers. It falls under the Coreopsis Grandiflora family. Characteristics include taller plants, reaching up to two feet, petals with notched edges, blooming from late spring right through to the fall.
Another species in the Grandiflora category, ‘Moonswirl’ could, at a glance, be mistaken for a marigold or chrysanthemum. The deep yellow flowers feature fluffy layers of petals that are referred to as semi-double blooms and is a pollinator magnet like its cousins. It would make a great cut flower and is both drought tolerant and disease resistant. ‘Early Sunrise’ is also a lovely, frilly variety.
The flowers of this grandiflora variety are about three inches across with petals that have almost serrated-looking edges. But it’s that deep burgundy-brown around the centre that really makes this a showstopper. This plant is hardy down to USDA zone 4 and doesn’t mind hot, humid summers.
Coreopsis ‘Gold & Bronze’
Part of the Uptick series, Gold & Bronze is a new hybrid. Flowers are supposed to be larger and bloom time longer. Plants grow in neat clumps, making them great for borders with taller plants behind. Foliage is mildew resistant. And how great would these look in a vase?
What varieties of tickseed do you grow?