Large Flowered Tickseed – A Complete Guide To Grow & Care

Native Range of Large Flowered Tickseed

The native range of Large Flowered Tickseed (Coreopsis grandiflora) is primarily in the Southern and Central United States. From Texas to Florida, north to Kansas and North Carolina. Also, within it’s native range there are several naturally occuring varieties recognized.[6]

Large Flowered Tickseed spread beyond it’s native range

Due to it’s adaptability and frequent use as an ornamental flower, Large Flowered Tickseed has escaped it’s native range and become established in a number of states in North America . It has established populations in Iowa/Wisconsin up to Southern Ontario Canada and New England.

Furthermore it’s use as an ornamental has made it a noxious weed in various parts of the world. It has been declared invasive in Australia, China, and parts of Europe.[7][8][9]

Large Flowered Tickseed Reference Table

Scientific Name	Coreopsis grandiflora
Common Name(s)	Large-flowered Tickseed, Largeflower Tickseed, Tickseed, Common Coreopsis
Native Range, USDA Zone	USDA Hardiness zones 4-9, Southern United States
Bloom Time	Summer
Bloom Duration, Color	Two months, Yellow
Height	12-24″
Spacing / Spread	12″
Light Requirements	Full sun
Soil Types	Sandy-loam to clay-loam, well-drained
Moisture	Dry to medium
Fauna Associations / Larval Hosts	Bees, butterflies

Identification and Characteristics of Large Flowered Tickseed

Stalk

The stem of Large Flower Tickseed is smooth, green, and round. Multiple stems will emerge from the root crown, and these will branch as well.

Leaf

The base of Coreopsis Grandiflora will have simple basal leaves that are lanceolate to ovate in shape with smooth margins, and are roughly 3-4″ long by 1-2″ wide.[2][3]

Upper leaves are opposite along the stalk are pinnately or pedately lobed with typically 3-5 lobes. The shape of the lobes are narrowly lanceolate to linear in shape, and 1/2″ -2″ long by roughly 1/4″ wide.[2][3]

Flower

Flowerheads form on long stems and are overall roughly 1-3″ diameter with 6-15 yellow ray florets surrounding a group of disk florets. The of the petal will have several notches.[2][3]

Blooming begins in late Spring and continues until late Summer, lasting 2-3 months depending on how much you deadhead it.

How to save seed

Several weeks after a bloom fades the flowerhead will turn brown and dry. Collect flowerheads at this time, and crush them over a plate. The seeds will fall out and have a shape that is somewhat similar to ticks, hence the name, tickseed.

Dried seed can be stored in an envelope or zip-lock bag for several years in a cool, dry place.

Root

The root system of Large Flower Tickseed are fibrous and spreading. Interestingly, the root system has been found to emit allelopathic chemicals which can inhibit the growth of other species – this effect has been noted in China.[10]

Grow and Care for Large Flowered Tickseed

Sunlight Requirements

Large Flowered Tickseed should be grown in full sun, which is at least six hours of direct sunlight per day. It will not be nearly as showy in partial shade.[3]

Soil Requirements

For soil texture, Large Flowered Tickseed isn’t too picky as long as it drains well. This plant does not like wet feet, so check your soil drainage before planting, or try to plant in a mound. [3][4]

Moisture Requirements

For moisture, Large Flowered Tickseed prefers dry to medium moisture and is fairly drought tolerant.

Deadheading

If you are trying to keep this plant looking it’s best, then deadheading spent flowers (almost daily) is a necessary chore. Also, cutting down all of the foliage to the basal leaves in late August will help increase the chances of this plant coming back the following year. [5]

Maintenance

Since Large Flowered Tickseed self-seeds, you should plan on removing new unwanted seedlings in the Spring. Large Flowered Tickseed can be cut to ground in late August, and this will increase the chances of it returning in the Spring. [5]

Fertilizer

Large Flowered Tickseed will not require any supplemental fertilizer. Fertile soil or applying fertilizer will likely cause it to flop over. [3]

How to Grow Large Flowered Tickseed from Seed

Large Flowered Tickseed is relatively easy to grow from seed but does have two dormancy mechanisms that need to be overcome. The first is that the seed must be surface sown, as it needs exposure to sunlight to germinate. The second is that germination rates will improve if it undergoes a 30 day cold moist stratification period.[11] This is most easily overcome via Winter Sowing, but the stratification can be done in the fridge as well.

One nice feature of growing Large Flowered Tickseed from seed is that it will often bloom the first year. But the plant needs exposure to cold weather to flower.[12] So, if you are germinating the flowers in Spring when nighttime temperatures get down to the 40’s or just Winter Sowing, then you will cover this requirement. But if the seed is germinated in June or later, it likely won’t flower until the second year.

Process to germinate Large Flowered Tickseed

The following steps assume you either have stratified the seeds in the refrigerator for 30 days, or are Winter Sowing.

1. Fill a suitable container with moist potting soil. The soil should be moist enough where if you squeeze a handful several droplets fall out.
2. Press 3-5 Large Flowered Tickseed seeds into the soil, ensuring good contact.
3. Water by misting with a spray bottle so that the seed doesn’t get covered.
4. Germination should occur within 2 weeks once temperatures warm up.

Direct sowing Large Flowered Tickseed

You can direct sow Large Flowered Tickseed in very late Winter or early Spring. Simply scatter the seed on disturbed soil and walk over it to ensure it has good contact. You can also direct sow in Autumn or Winter, but know that both birds and rodents love to eat the seed, and many will likely be consumed.

Wildlife, Pests, and Diseases associated with Large Flowered Tickseed

Pollinators

Large Flowered Tickseed attracts various bees, butterflies, and skippers. It will primarily attract smaller bees, such as sweat bees, which are not as noticeable. [3]

Mammals

Large Flowered Tickseed is deer and rabbit resistant. I have almost never seen damage to any of my plants. Also, mice and other rodents do enjoy eating the seeds when they fall from the seedheads.

Birds

Birds love to eat the seed of Large Flowered Tickseed. This is a strong argument for not deadheading the flowers, as it will feed the birds.

Disease

Large Flowered Tickseed is susceptible to rust, leaf spot, powdery mildew, and downy mildew. These diseases are a sign of stress on the plant, likely from too much or too little water. But the effects are only cosmetic, not fatal.[3][13]

Uses of Large Flowered Tickseed

Garden Uses

Large Flowered Tickseed can make for a very nice addition to a formal flowerbed, a short border, or planted along the street/sidewalk. It is rather adaptable and although it is often short-lived, it’s life can be prolonged by pruning in August. Or you can just let it self-seed a bit, as it will flower the first year anyway!

Just remember, if you grow it in fertile soil…it will flop over. But I must say, when it comes to plants that flop, Large Flowered Tickseed looks better than just about anything else laying down. It almost resembles a groundcover when it falls over.

Companion Plants

There are numerous companion plants that look good and can grow in similar conditions as Large Flowered Tickseed. Some of those are as follows:

• Aromatic Aster
• Dotted Blazing Star
• Hairy Beardtongue
• Lanceleaf Coreopsis
• Blunt Mountain Mint
• Hoary Vervain
• Virginia Mountain Mint
• Narrow-leaf Coneflower
• Tennessee Coneflower
• Prairie Smoke
• Wild Petunia
• Winecups

Medicinal Uses

I could not locate any medicinal use, nor Native American use of Large Flowered Tickseed.