Container gardens can create year-round color

Published 2:00 pm Wednesday, September 14, 2005

Most container gardens are like sci-fi movies, bursting onto the scene in a spectacular show of special effects, lasting just one season. Those splashy cascades of petunias and geraniums may be blockbusters, but with a little planning, you can have colorful container gardens that last all year long.

Fall is the best time to start an all-season container garden. Begin with the right pot. Plastic containers are probably the best for the purpose, since they’re light, inexpensive, and unlike their ceramic and clay counterparts, won’t crack in winter’s cold. Some of the new plastic pots that are made to resemble weathered clay look so real that you have to touch them to be sure.

Choose pots that are at least 14 inches deep and 16 inches across. Use a good quality potting mix, not garden soil. Add just a little time-release fertilizer and polymer granules that absorb water and release it as needed (available at nurseries).

First, select spring flowering bulbs such as tulips, daffodils and crocus. Plant them at the depth recommended on the package and add a handful of bulb food. On top of the bulbs, build your design around an arrangement of small evergreen plants, ornamental grasses and trailing vines. Pick plants with colorful foliage and contrasting textures. If this task seems daunting, ask your nursery professional for assistance.

Set the tallest plant either in the center or toward the back of the container. Allow trailing plants to cascade over the sides. Place a few smaller plants in the middle, leaving room for winter bedding plants such as miniature ornamental kale, winter pansies, dusty miller artemesia, small mums or asters.

In the early months of the new year, you may remove the winter bedding plants if they become ragged. In their place, tuck primroses in cheerful colors. Leave the evergreens and vines; they’re the permanent backbone of your arrangement.

Soon you’ll be seeing the bright green foliage of bulb plants peeping through. In spring, the primroses may be replaced with small seasonal annuals such as new pansies, English daisies, or forget-me-nots. Repeat this procedure in summer with alyssum, ageratum, lobelia, petunia, geranium, or other diminutive favorites.

If you want to keep the container garden going another year, next fall remove all plants and replace and replenish at least half the potting soil and amendments. If your “backbone” plants are still healthy, replant them in the same pot. If they’ve grown too large for the container, give them a new home in your garden.

A big, hollowed-out pumpkin makes a nice seasonal container. Insert nursery pots of coppery mums, purple asters, burgundy fountain grass, and gold and green variegated needlepoint ivy to trail over the edges. After Thanksgiving, you can settle the plants into your garden and toss the pumpkin into the compost.

The bronze-red foliage of chard, canna, or phormium (New Zealand flax) is a beautiful backdrop for fall flowers. Imagine them with magenta asters, frilly purple kale, and a graceful, arching ornamental grass, spilling from a weathered wooden crate or rustic wicker basket.

Container plants are subject to drying more quickly than those growing directly in the garden. Check them regularly to ensure they have enough water. Go lightly with the fertilizer or they’ll grow so quickly your arrangement will be out of scale. Keep faded flowers and dead leaves clipped.

If there’s an extended cold snap and you think the soil may freeze, move the containers into a garage or other frost-free area until danger of freezing is past. This is when you’ll truly appreciate those light plastic pots!

Island County-WSU Master Gardener Mariana Graham is on vacation through the end of September.