Coreopsis Verticillata Zagreb
'Zagreb' can spread in the garden by rhizomes and self-seeding, particularly in moist fertile soils
Easily grown in dry to medium wet, well-drained soil in full sun. Thrives in poor, sandy or rocky soils with good drainage. Tolerant of heat, humidity and drought. Prompt deadheading of spent flower stalks can be tedious for a large planting, but does tend to encourage additional bloom. Plants may be sheared in mid to late summer to promote a fall rebloom and to remove any sprawling or unkempt foliage. 'Zagreb' can spread in the garden by rhizomes and self-seeding, particularly in moist fertile soils.
Threadleaf coreopsis (also commonly called whorled coreopsis) is a rhizomatous perennial which typically grows in dense, bushy clumps to 1-3' tall. 'Zagreb' is more compact (to 1.5' tall) and features bright yellow, daisy-like flowers (1-2" diameter) with untoothed rays and darker yellow center disks. Flowers appear singly in loose clusters (cymes) in a lengthy late spring to late summer bloom period which sometimes extends to first frost. Shearing plants in mid-summer (early August) when bloom usually tapers down will encourage a fall rebloom. Palmately 3-parted leaves with thread-like segments lend a fine-textured and airy appearance to the plant. Plants in the genus Coreopsis are sometimes commonly called tickseed in reference to the resemblance of the seeds to ticks.
No serious insect or disease problems. Tends to sprawl, particularly if grown in moist and/or fertile soils. Crown rot may occur if grown in moist, poorly drained soils. Can be somewhat invasive in optimum growing conditions, but generally less so than the species.
Borders. Also effective in naturalized areas, wild gardens or cottage gardens. Good plant for areas with poor, dry soils.
© Missouri Botanical Garden, 2001-2006
Common: Zagreb threadleaf coreopsis
Location: Chicago Botanic Garden
Thread leaf coreopsis is a bushy, yet elegant, much-branched perennial with three-parted threadlike leaves arranged in opposite pairs or in whorls of three. The foliage looks a little like that of cosmos (Cosmos bipinnatus). Thread leaf coreopsis gets about 3 ft (0.9 m) tall and 2 ft (0.6 m) wide, and spreads slowly by thin underground stems (rhizomes). Flower heads are about 2 in (5.1 cm) across, and both disc florets and ray florets are yellow. Flowers are produced abundantly in loose, open clusters on thin, wiry stems in early summer until first frost. 'Moonbeam', probably the most popular cultivar, gets about 2 ft (0.6 m) tall and has smaller light yellow flowerheads about 1 in (2.5 cm) across, produced abundantly on a mound of lacy foliage. It was chosen by the Perennial Plant Association as the 1992 Perennial Plant of the Year. 'Zagreb' is smaller, to 12 in (30.5 cm) tall, with golden yellow flowerheads, and is even more resistant to drought than other selections
Thread leaf coreopsis grows naturally in the southeastern United States from Maryland and Virginia to West Virginia, Tennessee and Arkansas, and south to northern Florida. It occurs in dry, thin woods and open pinelands.
This planting of the variety 'Zagreb' is tough enough to easily survive this dry, semi-shaded location near the street
Divide the root crown every third year to maintain vigor and deadhead frequently to encourage more flowering. Rabbits may eat young plants.
Light: Full sun.
Moisture: Drought tolerant.
Hardiness: USDA Zones 5 - 10.
Propagation: Propagate the perennial coreopsis species by dividing the rhizomatous root crown in winter or early spring. Seeds germinate in 2-3 weeks and thread leaf coreopsis sometimes will self-sow.