Easy to grow, astrances are seducing more and more gardeners. A beautiful bright green foliage and a graceful bloom make of this very simple plant, a subject of choice to install in the semi-shaded corners of the garden.
The astrances, beautiful umbellifers
Part of the Apiaceae family (formerly 'Umbelliferae'), the genus Astantia includes a dozen species of perennial plants forming tufts with beautiful bright green palmate or palmate foliage.
The astrances are native to alpine meadows and undergrowth from Europe to Western Asia. Extremely hardy, they can withstand strong frosts but fear warm exposures and dry soils. In summer, these plants produce umbel inflorescences composed of collar-like bracts surrounding five-petalled flowers that are very popular with bees, bumblebees and butterflies. The color of the flowers varies according to the variety, on the Astrantia major species, the large astrance which is declined in many cultivars like 'Alba' or 'Star of Billion' with white flowers, 'Rubra' bright red, 'Ruby Weeding' or 'Roma' pink, or the very elegant 'Buckland' with white bracts contrasting with pale pink flowers. For those who love originality, 'Sunningdale Variegated' with its creamy white margined foliage is ideal for a shady spot.
These astrance varieties are ideal in flowerbeds or mixed borders with perennials, biennials and annuals such as monards, blueberries, alstroemeria or bellflowers. Then play with the pastel colors of astrances to contrast with other plants or to create textural effects as with orpins, ornamental garlic or echinacea. In this case, choose the most sun- and heat-tolerant Astrantia major cultivars. Astrantia major also works wonderfully as a border plant in the company of plants with ornamental foliage such as acanthus, hostas or heuchera.
Another species very appreciated in Astrantia maxima gardens that has large pink bracts with pointed tips that surround pale pink flowers. The diameter of the inflorescences can reach on this species nearly 7 cm in diameter, which makes it an outstanding ornamental subject.
The astrances reseed themselves from one year to another if the soil is suitable for them forming beautiful carpets that can still reach 90 cm in height on some cultivars of Astrantia major. The latter will do wonders in flowering meadows and bee fallows, where they will attract many pollinating insects.
Less sold, but present in nature, Astrantia minor is also very well suited for this use but it does not exceed 25 cm in height against 60 cm for the species mentioned above.
How to plant astrantia?
From their origins, astrances have kept a preference for fresh, humus-rich soils as in the undergrowth. For the same reason, they appreciate bright exposures but not the scorching midday sun.
In southern regions, plant them under the protection of tall trees or shrubs, elsewhere, they can tolerate the full morning or evening sun, especially the cultivars of Astrantia major created to better resist heat and full sun.
Plant the astrances in spring or autumn outside of frost periods by spacing them 30 to 50 cm apart depending on the varieties and the desired effect. If the soil is sandy or very well drained, add a good dose of potting soil and compost, not forgetting some well decomposed manure two weeks before planting.
Dig a hole twice the size of the root ball and place the plant so that the collar is flush with the soil level. The leaf rosette should not be buried to prevent it from rotting.
Water copiously to ensure recovery.
Pot planting is possible although the plant is easier to manage in the open ground because of its need for water. Plant it in good soil with compost, water and place the pot in full light without direct sunlight.
How to maintain astrance?
If you plant the astrance in spring or in a pot, make sure to water it very often and especially in summer. The soil should be kept cool but never soggy.
Mulch the plant with an organic mulch (dead leaves, mowing residues, straw, BRF...) to limit evaporation and weed competition.
In mid-spring, scratch a mixture of compost, crushed horn powder and dried blood at the base of the plant to ensure a beautiful summer bloom.
Cut off the wilted flowers as you go along to prolong flowering and prevent seeds from forming if you don't want the plant to reseed spontaneously.
At the end of winter, cut off the wilted foliage to give your plant a new look and induce the formation of new leaves.
The tuft will strengthen over the years but it tends to become exhausted and to age poorly, becoming dewy and flowering little. After 4 to 5 years, divide the clump into 4 parts and immediately replant them in another area of the garden.
The astrances, if grown in good conditions, are not very susceptible to disease, however aphids and slugs may appreciate them. Spray plant manure to keep them away, and treat aphids with black soap.
