Chrysanthemums and Asters

Chrysanthemums and Asters come into full bloom as fall arrives. These wonderful plants bloom in colors that personify autumn. Chrysanthemums come in orange, russet, burgundy, bronze, pink, yellow, and gold in every shade and combination you can image. Aster flowers are usually blue, purple, white, red or pink. These two plants are the back-bone of fall garden color.

Both species are part of the huge Asteraceae family that includes plants like marigolds, Shasta daisies, English daisies, sunflowers, goldenrod and dahlias. There is some confusion over the botanical name of plants in the Chrysanthemum family. Many different types of flowering plants used to be labeled as Chrysanthemum x morifolium. Taxonomists, as they sometimes do, divided this huge genus in 1999. This gave some former Chrysanthemums, like the shasta daisy, a genus of their own.

Starting in September garden centers offer blooming pots of Chrysanthemums. Although they are perennials, in zone 4 they should be treated as annuals. Buy a few containers full, pop them in the ground or a planter, and enjoy them while you can with no expectations for next year.

Chrysanthemums originally came from China and Japan, where they had been hybridized for centuries. There are literally thousands of cultivars that come in flower forms called buttons, pompoms, daisies, decoratives, spiders and spoons. Type depends on petal length, shape and form. They are all disk flowers with petals circling in rays from the center

I have grown Chrysanthemums from starts taken in the spring. These plants take a lot of care. They need rich, well-drained soil. They have to be pinched-back until mid-July to get the maximum number of blooms. They need plenty of moisture throughout the growing season while they offer the garden nothing but mounds of nondescript greenery. Then, to keep the plant healthy and get the optimal bloom, they need dividing at least every other year, preferably every year. Last, but not least, they are only reliably hardy to zone 5. I decided that buying plants and placing them in the fall garden was easier than growing them myself.

Even potted Chrysanthemums seldom survive the winter in our zone 5 areas. The root ball has been compacted into a ten-inch pot shape. The can't develop the extended root system to hold them in the ground before frost cuts off the growing season.

Asters are better perennial plants for northern gardens. These also have daisy-like flowers but are more airy looking than Chrysanthemums. Many are hybrids of North American natives so are already have genetically acclimated to our weather. Hardy Asters for this area are Aster alpinus, Aster novae-angliae (New England Aster) and Aster novi-gelgii (New York Aster or Michaelmas Daisy). They vary considerably in height, so watch plant tags to get an idea of the mature size of the plant you are buying. Some are six-inch miniatures (Aster alpinus). Others are six-foot giants that require staking. If you don't like staking plants or object to seeing the devices in the garden, shop for Asters of dwarf and medium sizes. Unfortunately, if you didn't buy Asters last spring you will have to wait to add them to your garden. Asters plants are usually bought in the spring to allow them to settle into the garden before they face winter.

Aster Yellows affect plants in the Asteraceae family. The link takes you to the Kemper Center for Home Gardening with the symptoms and how to deal with this viral disease.