How to plant and grow perennial sunflowers

How to plant and grow perennial sunflowers

Probably one of the most beloved and familiar flowers in the world, sunflowers have long been a favorite of borders and bouquets alike due to their huge, brightly colored blooms. Although it's not quite as large as its annual cousin, the perennial sunflower (Helianthus spp.) makes up for what it lacks in size with tons of blooms in late summer and fall.

Perennial sunflowers can usually be found in varying shades of gold, with a few varieties found in soft lemon yellow. Foliage varies among many sunflower species. While litmus leaves tend to be rough to the touch, there are some exceptions, e.g helianthus salifolius, Which has beautiful foliage. These plants only branch at the flowering tips, creating a very soft and airy texture.

Many perennial sunflowers native to the United States are hardy plants that come from the Great Plains, prairies and open rocky forests. They adapt well to a variety of conditions.

Perennial sunflower overview

Genus name Helianthus
Common name Perennial sunflowers
Plant type Standing
a light sun
to rise 2 to 10 feet
an offer 2 to 3 feet
Flower color yellow
Color of foliage Blue green
Season features Autumn bloom, summer bloom
Special features Attracts birds, cut flowers, low maintenance
Regions 4, 5, 6, 7, 8, 9
Spread Division, seeds
Problem solvers Deer resistant, drought resistant

Where are perennial sunflowers grown?

Plant perennial sunflowers in an area that receives full sun. The soil must be well-drained. Plant smaller perennial sunflowers at the front of the border, while taller flowers belong in the middle or back of a mixed bed or cutting garden.

If you plan to plant some tall varieties, be sure to stake them down as they are prone to flopping over, or plant them near other tall plants, walls or fences for support.

How and when to plant perennial sunflowers

Sow perennial sunflower seeds directly into the garden in the spring after the last frost date in the spring. Prepare the garden bed by loosening the soil to a depth of at least one foot and adding compost and organic matter. Make holes one inch deep and 12 to 18 inches apart, then drop a seed into each hole. Cover with soil. Seeds planted in spring may flower by fall, but perhaps not until the following spring.

Seeds can be sown in the fall in the same way as in the spring. After natural cold stratification for the winter, the resulting plants flower earlier than plants planted in spring.

To get a strong start to the season indoors, start eight to ten weeks before the last frost of the spring. Place the seeds in a plastic bag with the wet seed mixture and place them in the refrigerator for a month. Then fill the small pots with the wet seed mix and place one seed in each pot. Place the pots in bright light in a warm, dry location until germination occurs. When the soil warms in late spring, harden off the seedlings and transplant them outside.

Plant a few seeds every two weeks during the spring and summer to enjoy continuous blooms.

Tips for caring for perennial sunflowers

a light

To prevent stem stems, plant perennial sunflowers in full sun. This achieves the greatest possible bloom in the most compact habit. They will tolerate partial shade but are more susceptible to fungal diseases such as leaf spot and powdery mildew.

Soil and water

Perennial sunflowers grow best in well-drained soil with average moisture. However, many species are drought-adapted, while some, such as the swamp sunflower, prefer moist, swampy soil. Some perennial sunflower plants do well in average to poor soil, while others prefer nutrient-rich soil. Be careful with larger species; If planted in too rich soil, it may flop due to the abundance of growth.

Temperature and humidity

Perennial sunflowers tolerate heat, drought and high humidity. It thrives in sun and heat but can grow in slightly cooler weather as long as it is sunny.

Fertilizer

Fertilize perennial sunflowers once a year in the spring when new growth appears with a low-nitrogen granular fertilizer. (Nitrogen encourages foliage, not flowers.) Dig it into the soil 6 inches from the plant's trunk, following the product's directions.

pruning

Perennial sunflowers do not require much pruning. Cut plants back by two-thirds and remove any debris or damaged foliage in early spring.

Potting and replanting perennial sunflowers

Perennial sunflowers are not ideal container plants because they do not like to be transplanted. However, smaller varieties will thrive in a sturdy, well-drained container filled with a mixture of garden soil and compost. Choose a large container so you never need to repot the plant.

Pests and problems

It is known that aphids abound on perennial sunflowers in spring and early summer. It can be controlled by pumping water or using neem oil or insecticidal soap.

Perennial sunflowers grown in less than full sun are likely to encounter fungal diseases.

How to propagate perennial sunflowers

Propagate perennial sunflowers by division or seed.

to divide: Perennial sunflowers have spreading roots. Experienced gardeners recommend dividing perennial sunflowers every three years for plant health, but they can also be divided more frequently than that to produce new plants. Lift an established plant and root ball and use a sharp shovel or knife to cut off a section containing the rhizome and foliage. Plant the division in a prepared garden bed immediately or in pots filled with good quality soil.

seed: After the plant dies and the flowers dry, cut off the flower and part of the stem and place it in a bowl to catch any loose seeds. Tie a paper bag over the flower to prevent birds from eating the plant's seeds before they are ready to harvest. You can also cut the flowers early and hang them by their stems in a warm, dry area if they need extra drying time after being cut.

When the flowers are dry, place them over a bowl and rub them with your hands to release the seeds. Rinse the seeds in a strainer and remove any excess bits and pieces that are not seeds. Spread it in a single layer on newspaper or paper towels and leave it overnight in a warm, dry place. Store in a container until planting time.

Perennial sunflower species

Sunflower “Lemon Queen”.

David Speer

Helianthus 'Lemon Queen' is a bold plant that reaches 4-6 feet tall. Its single, light yellow flowers are produced in abundance from mid-summer to fall. Staking may be necessary if the soil is rich. Zones 5-9

Sunflowers “low down”.

Denny Schrock

Helianthus angustifolius 'Low Down' packs a tall, perennial sunflower cluster but only reaches 18 inches tall. It requires no staking and blooms from mid-summer to fall. Zones 5-9

Sunflower Swamp

Ed Golish

Helianthus angustifolius It bears masses of bright yellow daisies with purplish-brown centers atop 6-foot, bristly stems in early fall. Zones 6-9

Sunflower willow leaves

Peter Cromhardt

Helianthus salicifolius It features thin, delicate leaves on long stems with translucent yellow flowers and brown centers. It grows 8-10 feet tall. Zones 4-9

Companion plants for perennial sunflowers

Dahlia

Jim Krantz

Nothing beats dahlia for summer color. Growing these diverse and spiky flowers is like having a box of crayons in the garden. In mid- to late summer, flowers form on branched, fleshy stems or bloom in solitary splendor on bedding plants. Many different categories of flowers, from tiny mignonettes to giant dahlias on dinner plates, offer possibilities to fit any space.

Daylily

Peter Cromhardt

Daylilies are so easy to grow that you'll often find them growing in ditches and fields as escapees from gardens. However, they appear to be very delicate, producing gorgeous trumpet-shaped flowers in a myriad of colours. There are about 50,000 named hybrid cultivars in a range of flower sizes (small flowers are very popular), shapes, and plant heights. Some are fragrant. The flowers are borne on leafless stems. Although each bloom lasts only one day, superior varieties bear many buds on each scape, so flowering time is long, especially if you flower daily. Banded foliage may be evergreen or deciduous.

Salvia

Few gardens do not have at least one plant growing in them. Whether you have sun or shade, a dry garden or heavy rainfall, there is an annual sage plant that you will find indispensable. They all attract hummingbirds, especially red ones, and are great choices for hot, dry locations where you want lots of color throughout the season. Most salvias don't like cold weather, so plant them outside after all danger of frost has passed.

Garden plan for perennial sunflowers

Easy-care summer garden plan

The secret to the almost non-stop color in this easy-care summer garden plan is staggering flowering times. Low-maintenance perennials in this design produce an array of pink, purple, yellow and white flowers from spring to fall, but are at their best during the warmer months.

Frequently asked questions

  • How long do perennial sunflowers bloom?

    Most perennial sunflowers are late season plants and bloom for 8-12 weeks starting in mid to late summer.

  • Are perennial sunflowers dead?

    Cutting off dead flowers increases the number of flowers the plants produce, but deprives native birds of an important food source. Enjoy the best of both worlds by tying small paper bags over some flowers while you kill others. When winter comes, remove the bags and watch the local birds enjoy the seeds.

  • Which perennial sunflower produces the best edible seeds?

    Giant sunflowers (Helianthus giganteus), such as Giant Mammoth and California Greystripe, have large, seed-filled centers that produce the best seeds for roasting and eating.

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