By Shirley Froehlich

An article in Landscape Trades magazine for the Canadian Nursery and Landscape industry caught my attention recently. Our very own prairie native, Giant Hyssop (Agastache foeniculum), was the "Plant of the Month" in an article written by John Valleau of Valleybrook Gardens, a very large perennial grower in Ontario and B.C. It seems the nursery industry is beginning to see the value of some of our prairie species.

Giant Hyssop certainly has lots of things going for it. It blooms throughout July, August and into September. The flowers are alive with bees and butterflies coming for a drink from the nectar filled flowers. Goldfinches visit to eat the seeds too. It doesn't need to be left entirely to our wildlife visitors either. The licorice flavoured leaves make fine herbal teas and jellies or can be included fresh in salads.

I have found that it dries well for arrangements with long, sturdy stems. The flowers dry to a distinctive navy blue. It is also good as a fresh, cut flower. In fact it has been taken to Holland where selection and breeding work is going on to develop especially good forms for the commercial cut flower industry.

DESCRIPTION

This bushy, upright plant forms a nice sized clump and grows up to 90-100 cm tall (3 ft.) on the prairies. It is a member of the mint family with square stems and opposite leaves. The ovate leaves are medium green with a paler green underside. They are 2.5 to 7.5 cm long (1"-3") with a serrated edge. The 10 cm (4") lavender flower spikes are made of many small, tubular flowers packed together. Each plant produces a mass of flower spikes which results in a very attractive plant.

NATIVE HABITAT

Giant Hyssop has a fairly wide range. It can be found down through the mid-western United States as well as across the Canadian Prairies in Manitoba and Saskatchewan. I have seen it growing in both Bird's Hill Park and Riding Mountain Park in Manitoba. It grows in open woodlands, edges of aspen poplar groves and semi-open prairies.

Hyssop habitat at Bird's Hill Park.

CULTURE

In the garden Giant Hyssop grows very well in full sun or part shade. It tolerates a wide range of soils. Medium to moist soil is best, however the plant is quite drought tolerant once established. It self seeds somewhat, but not to the point of being a problem.

Groups of Hyssop can be used in newer beds where it makes a reliable, sturdy perennial for the middle or back of the border. It also mixes well with other wildflowers and native grasses to create a prairie meadow. It grows well in combination with other native species such as Early Blue Violet, Wild Strawberry, Northern Bedstraw, Canada Anemone, American Hedysarum, False Sunflower, Smooth Aster, and Hairgrass. This combination will give an ever changing tapestry of colour and texture throughout the growing season in either full sun or part shade.

Giant Hyssop can be started from seed indoors, or plants can be purchased to set out in spring after the danger of frost is past, or in summer. If you wish to start your own plants from seed indoors, they can be seeded in late March for planting outside in early June. The seed germinates in 6-10 days with bottom heat around 21 degrees C. Bottom heat can be provided by heating cables or by setting just above a hot air register until germination begins. Plants will bloom the second year from seed.

Giant Hyssop is a beautiful all around perennial for both prairie meadows and flower beds. Its abundant nectar and seed attract bees, butterflies, and birds to enrich your garden with flight and song. Cut and dried flowers enhance our homes and the leaves make tasty herbal teas.