Year 2
In 2009 we began a three-year evaluation of tickseed or Coreopsis. They are one of the most popular, best-selling perennials available today. Clearly, some of the native species deserve broader use in mainstream gardening. At the same time, there is a great deal of confusion among gardeners because some perennial cultivars do not perform as well as advertised. They may be short-lived perennials or in fact annuals. And sadly, many are also prone to pests and disease. Which are which? After careful evaluation in our trial garden, we will be able to help you find the best plants for your garden. In the meantime, check back regularly for insights, images and trial updates.
Mt. Cuba Center is located near Wilmington, DE, (USDA Hardiness Zone7A/6B). Five plants of each taxon are grown in full sun in an 11,000 sq. ft. trial garden protected from rodents by a 3’ tall wire fence within a 100-acre garden protected by a 10’ tall deer exclusion fence. The clay-loam soil in the trial garden has been amended over the years with composted leaves. It has an average pH of 7.3. The planting rows are mounded 2-4” to assure good drainage.
The trial garden is maintained with the home gardener in mind. Minimal maintenance includes watering to establish the plants and as needed in times of drought, and periodic weeding. One plant in each group is dead-headed for comparison. The beds are not fertilized, pesticides are not applied and plants are given no winter protection. Beds are mulched with hardwood bark to conserve moisture and suppress weeds.
Perennial plant trials at Mt. Cuba Center run for three years. If a plant dies during the first year of evaluation it is replanted in the spring of the second year. We look closely at flower form and size, color and longevity of the blooms. We evaluate plant habit with higher marks being given to plants with a uniform, sturdy, upright habit and lower scores given to plants that are lodging or sprawling. Disease and insect resistance combined with foliage appearance are also carefully considered.
Our numerical rating system ranges from one to five as follows: 5=Excellent, 4=Good, 3=Average, 2=Below Average, 1=Poor.
Flower Coverage: When the plant is blooming at its peak, what percentage of the plant is covered?
Plant Habit and Vigor: Does it remain upright and robust, increasing in size each year?
Pest and Disease Problems
Winter Hardiness
We have collected data on 13 species of Coreopsis including 45 cultivars and hybrid cultivars. You may look up a specific plant by scrolling through the alphabetical list of botanical names on the left side of the page or browse by name and picture on the right side of the page. Either way you will find the botanical name, the common name and an interim rating. The interim rating speaks only to the performance of a plant in that particular year. Each plant will receive a final rating only after the entire trial is finished.
When you click on the words “View all data”, a new page will open. There you will find a larger image of the plant. Clicking on “More Photos” will show you all of the photos we have available for that plant. Many will only have one image at this time. You will also find a short description of a plant’s performance. A graph has been added to give you a quick, general idea of a plants performance over the season. You may also print this page to keep for future reference to take with you to the garden center. On the top right hand side of the page you can click on the arrows to go on to the next page, back to the previous page or back to the very beginning.
Coreopsis auriculata 'Elfin Gold'
Coreopsis auriculata 'Zamphir'
Coreopsis (Big Bang™) 'Cosmic Evolution'
Coreopsis (Big Bang™) 'Cosmic Eye'
Coreopsis (Big Bang™) 'Full Moon'
Coreopsis (Big Bang™) 'Galaxy'
Coreopsis (Big Bang™) 'Half Moon'
Coreopsis (Big Bang™) 'Redshift'
Coreopsis (Big Bang™) 'Star Cluster'
Coreopsis 'Crèmbru' (Crème Brulée®)
Coreopsis grandiflora 'Domino'
Coreopsis grandiflora 'Early Sunrise'
Coreopsis grandiflora 'Mayfield Giant'
Coreopsis grandiflora 'Presto'
Coreopsis grandiflora 'Rising Sun'
Coreopsis grandiflora 'Sonnenkind'
Coreopsis grandiflora 'Sunburst'
Coreopsis grandiflora 'Sunfire'
Coreopsis grandiflora 'Sunray'
Coreopsis grandiflora var. saxicola
Coreopsis lanceolata 'Rotkehlchen'
Coreopsis lanceolata 'Sterntaler'
Coreopsis pubescens 'Sunshine Superman'
Coreopsis rosea ‘American Dream’
Coreopsis rosea 'Heaven's Gate'
Coreopsis rosea 'Sweet Dreams'™
Coreopsis tripteris ‘Flower Tower’
Coreopsis tripteris 'Lightning Flash'
Coreopsis tripteris - wild collected
Coreopsis verticillata 'Golden Gain'
Coreopsis verticillata 'Moonbeam'
5=Excellent, 4=Good, 3=Average, 2=Below Average, 1=Poor
