8 Perennial Flowers You Can Still Plant in August

Perennial flowers return year after year. They can return for two or three years or for decades, depending on the species. Though some people believe they’re not as showy as annuals, this isn’t always true. Some perennial plants feature spectacular flowers in all colors. Some biannual or even annual plants are treated like perennials because they self-seed so abundantly, but the following are true perennials that can be planted in August.

1. Lupines

These admittedly short-lived perennial flowers bring showy, pea-like flowers in colors from white to red to blue and purple. Some varietals are bicolored. Lupines grow best in hardiness zones 4 to 8 but live longer in the cooler part of their range and dislike the heat of the deep South. Lupines need a medium amount of watering and maintenance as well as full sun, though some varietals do well in partial shade. The plants also thrive in moist, well-drained loam that is a bit acidic. It is best to plant lupine side shoots as opposed to seeds. Lupines grow between 3 and 4 feet tall and have a 1-to-1.5-foot spread. They are usually avoided by deer and rabbits and attract pollinators.

The name lupine comes from the Latin word for “wolf.” The name was bestowed because people believed, erroneously, that the plant made the soil it grew in infertile.

2. Daylily

Daylilies are not related to “real” lilies, even though they look very much alike. They flourish in a wide range of hardiness zones, from 3 to 10. They get their name because their flowers, which can be small and dainty or huge and showy, last for about a day. The good thing is that they’re replaced by another flower that grows on a special branch called a scape. Daylilies come in every color and combination of colors but blue. Their leaves are strap-like, bright green, and have an elegant, fountain-like habit.

The plants aren’t particularly picky about soil, but a well-drained, moist loam is ideal. They range in height from 1 to 4 feet with a similar spread, and many are notorious for their ability to propagate. It’s not unusual to see colonies of these beautiful flowers growing by the side of the road or in abandoned places whose soil would not support most other plants. Eventually, they’ll crowd out most weeds and make a good ground cover. Daylilies also tolerate pollution and drought, and rabbits and deer don’t like them.

These flowers come as rhizomes. Plant those of the miniature plants about 18 to 24 inches apart, and plant larger varietals 2 to 3 feet apart. After that, they need very little care and shouldn’t even be fertilized too much. If your daylilies start to look crowded, divide them, plant the divisions somewhere else, or hand them out to friends and family.

3. Foxgloves

This plant is famous for its clusters of 2 to 3 inch long, bell-shaped flowers that bloom on 2-to-5-foot spires. The eye-catching flowers come in colors of pink, white, yellow, or purple, and their shape makes them a favorite of hummingbirds. Foxglove does best in hardiness zones 4 to 8 and though it prefers partial shade it does well in full sun if it’s kept well-watered. It loves fertile, acidic soil that must be kept moist. After it’s established, this perennial doesn’t need much care and self-seeds freely, which means that it will be a standout in your garden for many years. Rabbits and deer also tend to avoid it. Just be sure to remove most of the spikes after the flowers are spent. If they’re left in place, the plant starts to behave like a biannual.

One thing to keep in mind is that the foxglove is the source of the cardiac drug digitalis. Indeed, the plant’s genus name is Digitalis. The drug is found in the leaves and is very toxic, so beware.

4. Salvias

Salvias are basically types of sage. Common sage is grown both as an herb and for its beautiful blue flowers, which appear in whorls on square stems in late spring. Other types of sage have white, red, or blue flowers. Depending on the species, salvia can grow from 1 to 6 feet high and can flourish in hardiness zones 4 to 10. Be careful to learn what hardiness zone is best for your variety of salvia. These plants need full sun and well-drained soil that ranges from dry to medium moist. Make sure that the soil never gets too wet, for wet soil can kill the plant through root rot.

Plant smaller varieties of salvia 18 inches apart, and plant larger types 2 to 3 feet apart. Perennial salvia doesn’t grow well from seed, so propagate by division or from cuttings. The strong aroma of salvia, though attractive to humans, is off-putting to deer, and the flowers attract butterflies. Salvia is fairly free of diseases and pests.

5. Rudbeckia

Also called coneflowers, these perennial flowers grow best in zones 4 to 9. The flowers resemble daisies on wiry stems, but they are orange or yellow instead of white and surround prominent dark brown cones. The plants grow from 18 inches to 7 feet tall with a 3-to-4-foot spread. Coneflowers have attractive, deeply cut foliage along with their beautiful flowers.

Rudbeckia needs full sun for its best growth, though it can stand some light shade. Dry to average loam is ideal. The flowers are good for arrangements, even when they are dried. Plants can endure periods of drought and deer tend to ignore them. Plant 1.5 to 2 feet apart and propagate by seed or from division.

6. Crocosmia

This plant presents clusters of orange or red flowers that spring from a base of sword-like leaves. The flowers resemble small lilies and are beautiful choices for flower arrangements. At 1.5 to 4 feet high with a 1-to-2-foot spread, crocosmia also makes an excellent ground cover, for it grows quickly and suppresses weeds. It’s best planted in groups of a dozen or more.

Crocosmia grows best in hardiness zones 5 to 9 in full sun and moist, acidic loam that drains well. These perennial flowers grow from corms, and they should be planted 6 to 12 inches apart and 3 to 4 inches deep. If you live in a really cold climate, you may want to dig them up and store them in sphagnum moss until the warm weather returns.

7. Cornflowers

Cornflowers can be annuals or perennials, but one perennial type is Centaurea montana, or the mountain bluet. A member of the aster family, this unusual flower grows best in zones 3 to 8. It makes an excellent ground cover as it only grows from 1 to 2 feet tall with a similar spread.

These perennial flowers delight gardeners with their unusual look and ease of care. They are fringed, bright blue, with blue-violet centers. Some people think they resemble thistles that appear on the ends of erect stems. The plant’s gray-green leaves are also attractive. Cornflowers thrive in full sun and like well-drained soil with a medium level of moisture, though they famously tolerate dry soil and even drought. The plant also propagates through its stolons and may turn up in places where you don’t want it. Make sure to take out flower stalks after the flowers are spent and divide the plant every two or three years.

8. Poppies

The poppy plant is beloved for its flowers with tissue-thin petals in gemlike colors of orange, yellow, pink, red, salmon, or white. The leaves are grayish-green and fernlike. Depending on the species, poppies can flourish in hardiness zones 3 to 9, and grow from 12 inches to 4 feet in height. Make sure you know what zone your varietal thrives in, for some, like Papaver alpinum, can’t stand the heat and high humidity of summers in the deep South. Also, some poppies are best grown from cuttings while others are best grown from seed.

Poppies flourish in well-drained loam and full sun to partial shade. Make sure the soil is kept at least a little moist as the poppy doesn’t do well in soil that’s either too dry or too wet. When you plant it in August, make sure it’s mulched during the winter to protect it.

One Last Tip

Make sure that you cover seeds, bulbs, corms, or rhizomes with mulch after you plant them. If your plants are going to overwinter and you live in a cold climate, mulch protects your seedlings from frost heaving, which could kill them well before they bloom.