When it comes to long-blooming perennials, knautia (formerly known as Scabiosa rumelica), is one of the most whimsical. Its wiry stems dance in the wind and are topped with pincushion-like crimson flowers. This short-lived perennial will self-seed, making it a great candidate for informal and naturalized gardens, but it can become a nuisance in structured planting settings. However, the seedlings are a cinch to remove when they are young. This unfussy plant blooms from early summer into fall, producing months of garden color and bouquet-worthy blossoms.
Knautia Overview
Where to Plant Knautia
Knautia needs full sun and well-drained slightly alkaline soil. The easy-to-grow perennial is perfect for cottage and wildflower gardens or places where whimsy—and not order—is preferred. Some Knautia macedonica varieties are dwarf-like and tidy while other are tall (18 to 24 inches) and floppy. The upright but relaxed varieties look right at home in naturalized landscapes, meadowscapes, and prairie gardens. Dwarf varieties are perfect for sunny garden borders or containers.
Thanks to knautia’s nectar and pollen-rich flowers, it’s also a welcome addition to pollinator gardens. Expect bees and butterflies to visit frequently when your garden is in bloom. Plus, if the blooms are left unattended, seedheads will form and provide an appealing snack for birds.
How and When to Plant Knautia
Like many perennials, knautia is easiest to start from transplants purchased at a nursery or garden center. In the spring, dig a hole slightly deeper and twice as wide as the plant’s container. Knautia thrives in moderately fertile soil, so, if necessary, sprinkle some compost at the base of the hole before placing your plant. Backfill the hole with your displaced soil until your plant sits in the soil at the same depth as it was in its pot. If planting more than one knautia plant, place them 18 to 24 inches apart.
After placing your transplants, water them well and cover the soil around plants with a 2-inch-thick layer of mulch. Water plants regularly during the first growing season.
Knautia seeds require a little more patience but can be planted in late winter or early spring. After a period of cold stratification (about 3 to 4 weeks), sow the seeds outside as soon as the soil is workable. Moisten the top layers of soil and, if necessary, work in a little compost. Scatter the seeds on the surface in a sunny location. Sprinkle only a light layer of soil to cover as the seeds need ample light to germinate.
Knautia Care Tips
Knautia is an easy-to-grow, clump-forming perennial native to southeastern Europe. It is short-lived but will readily self-seed in optimal conditions.
Light
Sun-loving knautia needs full sun exposure (ideally 6-8 hours daily) to thrive. It can tolerate partial shade but will produce fewer blooms and have stunted growth.
Soil and Water
Knautia is tolerant of most soil types but struggles in wet and waterlogged soils. It prefers well-drained, slightly alkaline, moderately fertile soil.
Water new knautia plants once or twice weekly in the first year. In the second year, water them once weekly during the summer months and every other week in the fall and spring. In dry, mild winter climates (40˚ or warmer), knautia needs only occasional watering to keep from drying out.
Established knautia plants are robust and drought-tolerant. They are, after all, native to the meadows and scrublands where dry summers and rainy winters are common. In these places, rain is scant throughout the growing season, so plants have adapted to minimize water loss.
Temperature and Humidity
Knautia prefers sunny climates with cool summer nights. It may struggle in excessive heat and high humidity. It fares best in temperatures between 60˚ and 80˚ Fahrenheit. In freezing temperatures, knautia will die back to the ground. Temperatures below -5˚F will likely kill the plant—especially in moister climates. However, in the right conditions, knautia can self-seed and sprout new plants the following spring.
Fertilizer
In fertile soil, knautia requires no fertilization. If your knautia needs a boost, apply a balanced fertilizer at the beginning of the growing season. Avoid high-nitrogen fertilizers as they may limit blooming.
Pruning
Knautia will self-seed in optimum growing conditions. To prevent self-seeding, cut back or deadhead spent flowers as soon as you notice them. The plus side is, deadheading can also prolong flowering. In late winter or early spring, cut your plant back by half or almost to the ground. When cutting, prune the oldest stems first.
If you don’t mind your knautia spreading, leave the seeds and enjoy songbird antics. Birds love knautia and will forage the seeds over the winter.
Potting and Repotting
Knautia works well in containers if the pot is large enough (at least 5 to 6 inches in diameter) and has ample drainage. Mix your potting soil with perlite to increase drainage. Once your container is planted, keep it in a bright, sunny location (like a patio or uncovered porch).
Knautia is short-lived, so you shouldn’t need to repot it. If, however, your knautia plant has space to spread, plan to divide it every 3 to 4 years or when it outgrows its container.
Pests and Problems
Knautia is deer-resistant and has very few issues with pests (but may occasionally be bothered by aphids). The perennial is also relatively resistant to disease but may struggle if kept too wet.
How to Propagate Knautia
The easiest way to propagate knautia is via division. This can be done every three or four years in early spring. As soon as the foliage emerges, sink a spade into the ground and lift the entire clump. Cut the clump into several sections and replant divisions immediately. Water divisions well.
You can also collect knautia seeds from the seedheads at the end of the growing season. Allow the seedheads to dry out in a paper bag and shake loose the seeds once fully dried—be careful, they are tiny. Your harvested seeds can be planted outside in late winter or early spring. They do, however, require a period of cold stratification (3 to 4 weeks) to germinate.
Types of Knautia
Mars Midget Knautia
Knautia Macedonica ‘Mars Midget’ is a dwarf cultivar that grows approximately 12 to 18 inches tall in zones 5-8. It features domed, dark fuchsia flowers and deep green leaves. Its dwarf habit makes it slightly sturdier than other knautia cultivars.
Melton Pastels Knautia
Knautia macedonica ‘Melton Pastels’ grows 3 to 4 feet tall in zones 5-8. From early summer to the first frost, it bears domed, pincushion-like blooms in burgundy, mauve, pink, and salmon. This cultivar is also rumored to produce an occasional blue-hued flower.
Thunder and Lightning Knautia
The ‘Thunder and Lightning’ knautia cultivar grows 12 to 18 inches tall in zones 5-8. It features reddish-purple pincushion-like blooms and variegated foliage. The serrated green leaves of ‘Thunder and Lightning’ are edged in creamy white, creating a lightning bolt effect.
Companion Plants for Knautia
Black-Eyed Susan
Fast-growing black-eyed Susans are as much at home in a wild meadow as in a neatly cultivated garden bed—and they need little care to grow abundantly. They are a pollinator favorite and quite popular among birds. Come fall, it's not uncommon to see goldfinches, chickadees, and cardinals perched on the stalks plucking out the tiny seeds. Black-eyed Susans come as annuals, biennials, or perennials. Like knautia, they prefer full sun and well-drained soil. Most black-eyed Susans thrive in zones 4-9, but performance varies based on the cultivar and winter temperatures. They can be grown with some success in zones 3-11.
Coreopsis
Coreopsis is a highly adaptable group of plants, that work in nearly all garden settings. 'Moonbeam' coreopsis (Coreopsis verticillata), in particular, offers sunny contrast to knautia (in zones 4-9) with mounds of buttery yellow blossoms atop lacy green foliage. 'Moonbeam' coreopsis grows 18 to 24 inches tall and prefers full sun and well-drained soil. Like knautia, coreopsis is popular among pollinators but largely ignored by deer. It's a low-maintenance flowering plant suitable for beds, borders and containers.
Dianthus
Dianthus plants (often called "pinks") are cheery, easy-to-grow perennials. The cottage garden favorite features grass-like blue-green foliage and starry pink (or occasionally purple, red, white, or yellow) blossoms. Some even bear a sweetly spicy, clove-like scent. Like knautia, dianthuses prefer full sun and well-drained soil. They are hearty in zones 3-10.
Hardy Hibiscus
Hardy hibiscus may sound (and look) tropical, but the perennial is hardy in zones 4-9. So, it thrives in northern climates for years with the proper care. Hardy hibiscus plants (also called rose mallow) can reach up to 7 or 8 feet in height with dinner plate-size blooms in vibrant shades of red, pink, or white. It needs full sun and organically rich, consistently moist to wet soil. So, it won't tolerate as much drought as knautia. In cooler climates, choose the sunniest location to plant your hibiscus. In warmer climates, choose a spot with shelter from the harshest afternoon sun.
Jerusalem Sage
Jerusalem sage is a low-maintenance, drought-tolerant, semi-evergreen shrub that grows 2 to 4 feet tall in zones 7-10. In Zones 5-7, the soft, wooly, gray-green foliage dies back in the winter. However, Jerusalem sage roots are quite cold-hardy; so, there is a good chance that the plant will come back the following spring. If it does, it's worth the wait. In late spring, lemon-yellow, snapdragon-like flower spikes arrive, attracting a parade of bees, butterflies, and hummingbirds.
Penstemon
Penstemons (hardy in zones 3-8) come in a rainbow of colors and stand up to intense growing conditions. Like knautia, the deer-resistant perennials prefer full sun and well-drained soil. There are hundreds of species of penstemons to choose from but look for a variety that blooms alongside knautia in midsummer, like Penstemon digitalis 'Husker Red'. It grows about 2-1/2 feet tall and features deep maroon foliage and spires of white flowers.
Frequently Asked Questions
- Does knautia make a good cut flower?Knautia makes an excellent cut flower—especially in wildflower bouquets. Use it as a filler in lush arrangements or dry it to use in decorating projects.
Knautia makes an excellent cut flower—especially in wildflower bouquets. Use it as a filler in lush arrangements or dry it to use in decorating projects.
- How long do knautia plants live?Knautia is a short-lived perennial that may last 2 to 3 years. However, if left to self-seed, it will continue to produce new plants each spring.
Knautia is a short-lived perennial that may last 2 to 3 years. However, if left to self-seed, it will continue to produce new plants each spring.
- Why won't my knautia plant bloom?There are several likely reasons why a knautia plant would fail to bloom. First, check your plant’s sun exposure. Knautia plants need 6 to 8 hours of full sun each day to produce the best blooms. Next, check your plant’s soil and drainage. If the soil is too wet or draining poorly, amend it or install a drain tile to improve drainage.
There are several likely reasons why a knautia plant would fail to bloom. First, check your plant’s sun exposure. Knautia plants need 6 to 8 hours of full sun each day to produce the best blooms. Next, check your plant’s soil and drainage. If the soil is too wet or draining poorly, amend it or install a drain tile to improve drainage.