Asters

The New England Aster is a common plant for Zone 4.  Flowers are lavender to violet and yellow centers 1-2” wide.  Flowers bloom on the stem ends in late August through October.  The plant flourishes in moist acidic soil. Mature plants have woody stems and fibrous roots. 

Asters are mostly maintenance free but some mature plants can become top heavy and require support.  A general low nitrogen fertilizer will help reduce the green foliage growth and produce more blooms.  Trimming buds in late May encourages the growth of a bushy plant that is more stable during heavy wind and rainstorms. Divide the plant every three years to encourage vigorous growth.

There are several other native aster species to explore each with different characteristics. They range from tall branching plants to shrubs to ground covers. Flowers are blue to violet or white. Some native aster species are:

• Purple Dome- Dwarf grows 18-24”, deep purple flowers in late summer

• Heath aster- Native to MN prairies and woodland edges, compact 

• Smooth Aster – blue-violet flowers on 2-3’ stems, late summer

• Sky Blue Aster – similar to Smooth Aster but likes dry, sunny site

• Heart-Leaved Aster - Native to SE MN with white to sky-blue flowers

• Calico Aster – shade plant with small white flowers and 2-3 tall

• Aromatic Aster - Native to SE MN. More drought tolerant, late bloomer

• Big Leaf Aster – shady groundcover with large leaves and tall white flowers

Check out this article in Northern Gardener for more information about these asters.

Companion plants are goldenrod, grasses, oxeye, obedient plant, and showy tick trefoil.  The combinations create a colorful late season pollinator garden.  Asters are a colorful bloom in late summer and a critical fresh food source for migrating pollinators.

Hyssops

Minnesota native hyssops (Agastache Foeniculum) are another late summer bloomer and fall pollinator.  All plants are native to dry areas throughout Minnesota.  Hyssops bloom in late summer-fall and are another valuable nectar source for bees, hummingbirds, and butterflies.

Anise hyssop, also known as Blue Giant Hyssop or Lavender Hyssop is a pollinator magnet beloved by bees, butterflies, hummingbirds and moths. They have light blue-violet tubular flowers on 2-4’stems. They will grow in full sun to part shade and in dry fields and bloom throughout the summer. This plant is also deer resistant.

Hyssop is a lovely addition to the urban garden.  The attractive light green lance shaped leaves set the plant apart from other zone 4-8 perennials.  All hyssops self-sow but the volunteer plants are easily pulled. Hyssop will grow in a perennial garden or border planting in full sun to partial shade in well-drained soil. 

Hyssop is an herb.  Anise hyssop’s scented leaves can be harvested for tea, for salads, and other drinks. A member of the Lemnaceae family, hyssop is a shrub that is also native to SE Europe, Middle East and the region around the Caspian Sea.  It has an interesting herbal medicinal history being used as an antiseptic, cough reliever, expectorant, and abortive during medieval time.

Other hyssop cultivars include: 

• Golden jubilee- gold-colored leaves & is 20” tall.

• Alba and snowspire- white-flower spikes on top of 36” stems.

Companions to hyssop include goldenrod, black-eyed Susan, and coneflower.

Native asters and hyssops are not only a beautiful addition to any garden, they are an essential food source for pollinators; particularly late in the summer season. 

Sources:

ext.umn.edu/native-plants

www.webmed.com

Steiner, Lynn, D. Landscaping with native plants of Minnesota.  MBI Publishing, China, 2005

Northern Gardener Anise Hyssop and Asters

Photo Credits: Northern Gardener, Benjamin Vogt (1), Minnesota Wildflowers, Katy Chayka