If you love the bright yellow sunflowers, you don't have to be content with the annual species - there are a whole range of perennial varieties that are also known as perennial sunflowers. Their sunny flowers are significantly smaller than those of the annual forms, but they are even more numerous. Once planted, all species are extremely easy to care for and will give you many years of enjoyment.
What are perennial sunflowers and how do they grow?
Perennial sunflowers are perennial plants with bright yellow flowers that are deciduous and are native to North and Central America. They prefer full sun locations, are easy to care for, provide food for insects and can grow to a height of between 100 and 300 cm.
Origin and distribution
All approximately 67 known sunflower species are native to both North and Central America from Mexico to Canada, with each variety having its own specific natural range. The sunflower genus (bot. Helianthus) belongs to the daisy family (bot. Asteraceae) and is particularly popular because of its bright yellow, multi-rayed flower heads.
Appearance and growth
Perennial sunflowers form numerous, upright growing and rather thin stems on which the numerous flowers are located. The height varies depending on the species and variety - while some of the perennial species can grow up to 300 centimeters high, others only reach a height of 100 to 120 centimeters. What is typical, however, is the strongly branched and thickened rhizome, from which additional shoots sprout in most species. Perennial sunflowers usually grow in clumps and form more or less numerous runners.
Usage
All types of perennial sunflowers are valuable food plants for bees and other insects, even if they are often otherwise sterile hybrid breeds. Depending on the height and width of growth, some species are very suitable for area planting, while others are more effective as solitary plants. The flowering plants decorate mixed or pure perennial beds or borders and can be used as borders, as privacy screens or as planting at the edge of trees. The bright yellow flowers look particularly striking as a background planting in front of other perennials with blue, purple or red flowers such as delphiniums, Indian or scented nettle, monkshood, yarrow, chrysanthemums or asters. Low-growing varieties can also be cultivated in pots and can therefore also be found on the balcony or terrace.
leaves
Depending on the type and variety, the leaves of the perennial sunflower have a different appearance. The most common form is the same as that of the annual species: sawn or entire-edged, ovoid and large leaves with rough undersides. However, there are also other shapes such as the narrow leaves of the willow-leaved sunflower. In some species the foliage is only located at the base of the stem, in others they are distributed over the entire stem. All summer flowers are summer green.
Flowers and flowering time
The flowers of the perennial sunflower are similar to those of the annual species, although the lemon to golden yellow ray flowers are usually significantly smaller. However, the perennial varieties produce not just one, but very numerous flowers. These can be simple - with the characteristic darker center - but also semi-filled or filled. Most varieties bloom in late summer between August and September, but some also show their splendor until the first frost in October or even November.
Fruits
Perennial sunflowers, like their annual relatives, also produce edible sunflower seeds. However, this does not apply to all species, as many cultivars are sterile and therefore do not develop fruits or seeds.
Toxicity
All Helianthus species are non-poisonous.
Which location is suitable?
Perennial sunflowers bloom best in a full sun, warm and protected location. The following applies to these plants: the more sun, the better - because if it is too dark, only a few flowers will be produced.
Floor
Basically, perennial sunflowers feel comfortable in a location with nutrient-rich, humus-rich, sandy-loamy and well-drained garden soil, as long as it is not too heavy and has a neutral to alkaline pH value. However, there are different preferences between the different species when it comes to the moisture of the subsoil: some prefer a rather dry soil, while others prefer a fresh to moderately moist one. However, all species tolerate drought quite well.
Planting / Sowing
You can grow young plants on your windowsill at home from late winter and plant them out in the bed after the ice saints. The seeds germinate quite irregularly at around 20 degrees Celsius within seven to 21 days. Be sure to adhere to the recommended planting distance for both home-grown plants and seedlings - this is between 80 and 100 centimeters, depending on the species and variety. Mix the excavated material with plenty of compost and then water the freshly planted perennials vigorously. It is also advisable to dig in support rods so that the tall stems do not bend or break.
Watering and fertilizing
Although perennial sunflowers are quite drought tolerant, you should not let them dry out. Provide them with plenty of water, especially during hot and dry phases, but avoid moisture or even waterlogging. Fertilizing with mineral or nitrogen-rich fertilizers makes little sense, as this negatively affects the flowering. Instead, provide the perennials with plenty of compost in early spring and again in June.
Cut perennial sunflowers correctly
Since some varieties like to self-seed, you should remove spent stems as soon as possible. This also has the advantage that the cut provokes a longer flowering phase. Some species should also be cut back close to the ground in autumn or spring as they sprout new ones from the rhizomes.
Propagate perennial sunflowers
Perennial sunflowers are easy to propagate both from seeds and from cuttings cut in early summer. In addition, the clump-growing plants should be divided about every three to five years - this primarily serves to rejuvenate them and ensures lush flowers.
Wintering
Although perennial sunflowers are hardy, they should be protected from frost during the cold season with a cover in the form of brushwood or similar. The rhizomes - the perennial's overwintering organs - are located quite close to the surface of the earth and are therefore at risk from ground frost.
Diseases and pests
Perennial sunflowers are robust garden plants that are rarely affected by diseases or pests. Powdery mildew can be a problem, especially with the large-leaved species.
Tip
The always hungry snails also enjoy the juicy foliage of young plants. Snail protection is therefore important.
Species and varieties
In contrast to the annual sunflower species Helianthus annuus and Helianthus uniflorus, the perennial sunflower is a perennial representative of this attractive genus of flowering plants. However, this is not a single species, as there are a whole range of different varieties available for the home garden. Even if they differ in many external characteristics, they all impress with a rich and long-lasting flower bloom. The following types are particularly popular:
Perennial sunflower (bot. Helianthus atrorubens)
This spreading and bushy growing species produces inflorescences up to 180 centimeters high and can be up to 100 centimeters wide. The flower bowls, measuring more than ten centimeters in diameter, delight the viewer with their bright yellow pile between the beginning of August and September. Helianthus atrorubens should be planted in groups in the garden with a maximum of two plants per square meter and is particularly suitable for planting larger open spaces as well as borders of beds and trees. You can also use the long stems wonderfully for flower arrangements - for example in a vase. Particularly beautiful varieties include:
- ‘Giganteus’: imposing, rapidly spreading, sterile
- 'Monarch': bushy growth, clump-forming, sterile, lush flowering
Narrow-leaved sunflower (bot. Helianthus decapetalus)
This is probably the sunflower species with the most cultivars. Helianthus decapetalus impresses with its dense, clumpy growth, flower stalks up to 180 centimeters high and flower heads measuring an average of twelve centimeters. Plant the species in humus-rich, not too dry soil. The most beautiful varieties for the garden are:
- 'Capenoch Star': up to 180 centimeters high, upright growth, light yellow flowers, forming runners
- 'Loddon Gold': golden yellow, double flower balls, growth height up to 140 centimeters
- 'Meteor': semi-double, plate-shaped flowers with a darker center, height up to 180 centimeters
- 'Soleil d'Or': large, deep yellow and double flower balls, height up to 160 centimeters
- 'Triomphe de Gand': large, light yellow, plate-shaped flowers with a darker center, height up to 150 centimeters
Giant sunflower (bot. Helianthus giganteus)
The largest sunflower species develops flower heads up to 300 centimeters high and only shows its flowers late between September and the first frost. Plant the species, which reproduces through numerous runners, with plenty of space - a maximum of one plant per square meter is recommended. One of the most beautiful varieties is 'Sheila's Sunshine' with its bright, cream-colored flower heads.
Small-flowered or small-headed sunflower (bot. Helianthus microcephalus)
This species grows loosely branched and - in contrast to other perennial sunflowers - does not tend to overgrow. It produces small but very numerous flowers that unfold their splendor between August and September. The species needs nutrient-rich, humus-rich and fairly fresh soil. Here, too, there are many interesting cultivars for the gardener:
- 'Anne': lemon yellow flowers with red tips, unusually wide petals, flowering begins in July
- 'Carine': very bright, delicate yellow flowers, lush flowering, long-lasting flowering, growth height up to 180 centimeters
- 'Lemon Queen': lemon yellow, very lush and long-lasting flowers, growth height up to 180 centimeters
Hairy sunflower (bot. Helianthus mollis)
Between August and September, the hairy sunflower - which owes its name to the rough hair on the stems and leaves - delights with numerous, multi-rayed, bright lemon-yellow flower heads. The species grows up to 120 centimeters high and forms dense clumps. Plant them in well-drained and rather dry to fresh soil.
Willow-leaved sunflower (bot. Helianthus salicifolius var. orgyalis)
The willow-leaved sunflower, which grows up to 300 centimeters high - sometimes called a fathom-long sunflower due to its tall growth - is mainly cultivated for its distinctive, deep green leaves. In addition, the decorative foliage perennial shows numerous small, bright yellow flower heads from September until the first frost. The attractive solitary perennial, which grows up to 200 centimeters wide, feels most comfortable in humus-rich, rather dry soil.
Jerusalem artichoke (bot. Helianthus tuberosus, also Indian tuber)
Some people may recognize Jerusalem artichoke from the well-stocked supermarket, because the brownish tuber is a very he althy winter vegetable. What is probably less known is that these are the root nodules of a sunflower species. Helianthus tuberosus, also known as Indian tuber, grows up to 300 centimeters high and blooms between September and November with bright yellow flower heads. Like all sunflowers, this species is very bee-friendly and prefers moist but well-drained soil.
