Knautia

( NAW - tee - uh )

At-A-Glance Information

This genus, commonly called Widow Flower or Scabious, includes species of flowering herbaceous perennials. These flowers grow well in full sun when given regular water and are perfect in cottage or informal gardens. They are considered meadow or prairie plants, and are easy-care additions to any garden. Blooms are playful additions to cut flower arrangements as well. Plants range in size, but garden cultivars typically reach between 18 and 36 inches tall. They are great in mixed beds and borders, used as long-lasting color and airy charm.

Knautia Species and Varietals

The genus Knautia is a member of the plant family Caprifoliaceae and includes 55 species. Species in this genus are closely related to those in Scabiosa. Kautia grows best in USDA hardiness zones 5-9 or Sunset growing zones 2-10 and 14-24. To find your zone, click here: Zone Map.

Knautia arvensis (Blue Buttons, Field Scabious, Meadow Widow Flower)
This plant is native to Europe, the Mediterranean and the Caucuses and reaches 1-5 feet tall and 1.5 feet wide. Flowers are blue and bloom in the summertime. They are commonly found on roadsides and in field margins, and love growing in disturbed soils. This species is considered invasive in Canada and the Midwestern and Pacific Northwestern regions of the United States.

Knautia drymeia (Hungarian Widow Flower, Scabious, Pincushion Flower)
This species is native to central and southeastern Europe, and was first formally described in 1856 by Austrian botanist Johann Heuffel. Flowers can be scarlet, red, purple, pink or (rarely) white and bloom from June through September. Individual plants can reach up to between 1.5 and 2 feet tall at maturity when in bloom. This species is considered somewhat invasive in South Africa.

Knautia macedonia (Macedonian Scabious, Crimson Scabious, Pincushion Flower)
This native of Central Europe grows 1.5-3 feet tall and just as wide. Flowers are deep maroon and bloom in summer and fall. Reseeds somewhat freely. Varieties include 'Mars Midget' (16 inches tall with crimson flowers), those in the Melton Pastels group (to 1.5 to 3 feet tall; flowers come in blue, mauve, pink, rose, salmon-pink, and crimson), 'Alba' (with pure white blooms) and 'Thunder and Lightning' (with vibrant variegated green and white foliage). 

Caring for Knautia

Plant Knautia in full sun; ideally these plants should be getting between 6 and 8 hours of sun each day. They prefer to be planted in well-draining, moderately fertile soil with a pH of between 6.0 and 8.0 (slightly acidic to slightly alkaline). If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Water newly planted Knautia regularly to help it develop a strong root system. At maturity, these plants are drought-tolerant, able to get by on rainwater alone with some supplemental waterings in the warmest months of the year. Mulch around the base of plants to suppress weed growth, increase soil moisture retention, and maintain consistent soil temperatures.

Fertilize yearly in early springtime with a application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. These plants are not heavy feeders, and this should be sufficient to provide the necessary nutrients for the active growing and flowering seasons. Pruning Knautia plants is simple: remove spent blooms and any unsightly foliage. These plants will self-seed in optimal growing conditions to prevent this behavior, deadhead regularly. In late winter or early springtime, the entire plant can be cut back by half or almost to the ground. Knautia plants are considered perennials, typically lasting for between 3 and 6 years before needing to be replaced. They will freely re-seed in the landscape, providing new plants indefinitely.

Propagation

Knautia can be propagated either by division or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the division method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your Knautia flowers, follow the instructions below:

Propagating Knautia by Seed
  1. Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. The best potting medium for seed germination is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
  2. Harvest your seeds. The seed heads on plants are pretty easy to spot, they're left behind after flowers have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will continue to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
  3. In either late winter or early springtime, get your container prepared. Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 2-6 weeks from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
  4. Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 65 and 72 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.

Propagating Knautia by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil, compost and pots (only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in very early spring (after the plant has entered dormancy, but before it has begun its new spring growth), and needs to be done every few years regardless of whether you have the goal of propagating the plants for best performance. To propagate by division, follow these steps:
  1. Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the root(s). Once you have worked it up out of the ground, lay it out.
  2. Start to tease apart the roots with your fingers. Once the roots are untangled, separate your plant into segments, ensuring that each one has at least one thick root section attached.
  3. Prepare your pot(s) or new planting site(s) with amended, well-draining soil. You can either bring in new soil or simply amend your existing soil with compost to complete this task. Then, plant your divisions and water thoroughly.
  4. Apply a thick layer of mulch over the new planting to protect it from cold weather as it acclimates to its new home. Then, enjoy watching it sprout in the next growing season.
Knautia seeds.

Problems and Pests

Certain Knautia species are considered invasive in some regions; see the species descriptions above for more information. Check with local authorities before planting. Knautia plants aren't particularly susceptible to developing issues with pests and disease in the landscape, though they can suffer from the following from time to time if growing conditions are poor:
  • Aphids
For more information on these issues, including how to treat and solve them, consult the following pages:
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Gallery

Knautia plants form a basal tuft of foliage from which tall flowering stems emerge.
Knautia and white Gaura form a great pair.
This mixed border features Knautia and Agastache.
Two differently colored Scabious planted together can create a wonderful effect.
Knautia is a low-water use plant, here accompanying Blue Fescue and other drought-tolerant ornamentals.
Bees and many other pollinators love Knautia flowers.

Videos

A compilation video of Knautia pollinators.

Resources

Knautia macedonica
How to Plant and Grow Knautia
How to Plant, Grow, and Care for Knautia
Knautia Plant Info - How to Grow Knautia Flowers
Wikipedia: Knautia
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Page 393, Knautia