will keep plants vigorous, though an
easier solution is to let self-sown
seedlings take the place of tired plants.
related plantS Coreopsis tripteris
‘Lightning Flash’ sports glowing yellow
foliage in spring which fades to green
in summer. It may flop during
flowering. ‘Flower Tower’ reaches 8 ft.
and has thick, sturdy stems to support
its tall bouquet of late summer
blossoms.Coreopsis verticillata
threadleaf coreopsis
compoSitaeYellow flower heads; feathery green leaves
2–3 ft. high; 2 ft. wide
Full sun
Blooms June–October
Zones 3–9
pruning First-year plants may flower
all summer long even without
deadheading, but older plants require
deadheading for best performance.
They flower in early and midsummer
and then sporadically, or they may rest
totally in August and then rebloom in
September and October. For a stronger
and more attractive rebloom in
autumn, plants can be sheared in
August to remove deadheads, along
with the few flowers that may be
blooming at the time, using hedge
shears or even a string trimmer for
large plantings. Clean up pruned
branches by hand or with a small
shrub rake. Deadheading also pre-
vents reseeding. Plants with dead-
heads left on from the second bloom
phase contribute to winter interest.
Unless you want to avoid seeding, do
not prune again until early spring. If
seeding is a concern, cut down in
autumn—string trimmers can be used
at this time as well.
other maintenance Can spread
invasively by underground stems,
particularly in moist, sandy soils.
Divide as needed every 2–3 years in
spring or autumn. Long-lived.
Requires well-draining soil, and is
drought tolerant. Overly fertile soil
leads to sprawling habit. Cultivars
perform better than the species in
areas warmer than zone 6 or 7.
related plantS Cultivars of
Coreopsis verticillata should be pruned
as described above for the species,
although I have not witnessed
reseeding of cultivars so I leave them
for winter interest. It should be noted
that first-year plantings usually don’t
need any deadheading to be attractive
throughout the entire season. ‘Golden
Showers’ most likely needs staking.Coreopsis tripteris