4 groups of cool-season flowers

Daniel Gill  |  12/1/2015 9:55:01 PM


This is the time to plant cool-season bedding plants in your flower beds. These plants will thrive in the cool to cold weather of fall to spring and keep your flower beds looking attractive.

I have begun to divide cool-season bedding plants into four categories based on how we plant them and when they bloom. I’m trying to come up with short, appropriate names for these groups, but here’s what I have so far: “bloom all season group,” “take the winter off group,” “plant in fall and bloom in spring group,” and “plant me early and young group.”

What every category has in common is that a fall planting generally gives the best results.

Bloom all season

These are among the most useful and popular of the cool-season bedding plants. Blooming transplants are available at local nurseries and garden centers now. They are planted in bloom in the fall, and they continue to bloom all through our mild winter with a big crescendo of flowers in March and April. Planted now, in other words, they will provide flowers in your gardens for five or six months. Now that’s what I call a big bang for your gardening buck.

In this category, you will find pansy, dianthus, alyssum, viola, calendula, stock and ornamental cabbage and kale (grown for their colorful foliage). I think diascia, nemisia and toadflax also fall into this category, but flowering may be reduced in midwinter.


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Take the winter off

You can purchase blooming transplants of plants in this group now. Purchasing plants in bloom is nice because it allows you to select just the shades of colors you are looking for. Blooming transplants also provide immediate color to the landscape.

In the case of these cool-season bedding plants, though, blooming is reduced or stops as the short days and long nights of midwinter approach. When they go out of bloom, however, these plants continue growing large, strong root systems and robust leaves and stems.

You might ask, if you only get a little color in the fall and the biggest display is the spring, why not just wait until then to plant. The reason is the winter growing period. No cool-season bedding plants planted in spring will measure up to the spectacular display of large, well-established bedding plants that have been in the ground since fall. The best spring displays are almost always from a fall planting.

The two most popular bedding plants in this category are petunia and snapdragon.

Violas

Plant in fall and bloom in spring

A few cool-season bedding plants are best planted by seed in fall but don’t bloom until spring. You cannot wait until spring to plant seeds of these plants and expect a good display of flowers. They need the winter growing season to produce strong, robust plants that will produce an outstanding display of blooms in spring.

Most of these plants resent transplanting and are best direct-seeded right where they are to grow. Plant the seeds in well-prepared soil at the depth recommended on the package – smaller seeds are simply scattered over the area and pressed in. Be sure to thin the seedlings to the appropriate spacing. If you allow the plants to grow too crowded, you will be disappointed with the results.

Their foliage is hardy and will not be bothered by winter freezes. Growth will be relatively slow through winter and then pick up as the weather warms in February. By March, these plants will come into bloom and bloom until late April or early May.

This category includes all of the annual poppies, including Shirley poppy (Papaver rhoeas), Iceland poppy (P. nudicaule), California poppy (Eschscholzia californica) and peony-flowered poppy (P. somniferum). Sweet peas also fall in this category. Plant seeds soon for this beautiful and outstandingly fragrant, spring-flowering vine. Also in this group are bachelor’s buttons (or cornflower) and larkspur. All of these plants will commonly self-seed, and you may see new seedlings show up each fall in areas where they grew the year before.


Dianthus

Plant me early and young

This group primarily includes hollyhock, delphinium and foxglove. Although these plants may be perennials in other parts of the country, they typically do not survive the summer here and are grown as cool-season annuals. The biggest mistake in planting these is waiting until March or April and planting small plants in 4-inch pots already in bloom. You will be disappointed with the results.

The trick is to plant young, not-blooming transplants in fall or by February at the latest. This allows the plants to grow into large, well-established plants before they bloom. Handled this way, all three of these plants will bloom as early as March and as late as May and produce the large, showy spikes of flowers you expect.

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