News Release
June 25, 2007

 

Landscaping Tips: Container gardens add splashes of color to homes and landscapes

By Karen Panter,  Extension horticulture specialist, UW CES

Planting flowers and other plants in containers is a great way to add splashes of color to homes and landscapes. Container gardens are also ideal for those having small yards or those who have physical impairments but still like to garden.           

Most herbaceous plants, and even some dwarf shrubs and trees, can be successfully grown in containers.

Containers

There are basically two types of containers: porous and non-porous. Porous types, like those made of clay, allow for air and water movement. Soil in these pots can dry out quickly. Non-porous containers, like plastic, glazed pottery and metal, do not lose moisture nearly as fast.         

Almost anything can be used, provided it’s clean and has holes in the bottom to allow drainage. This helps prevent root rot by keeping roots out of sitting water. If no holes are present, drill a few.

Container size is a consideration. The rule of thumb is the larger the container, the longer it will take to dry out and the less watering it will need. Small pots and hanging baskets may require watering several times a day in Wyoming’s dry air.

Clay and pottery tend to be heavy. Once they’re full of potting mix and plants, they are not easy to move. Plastic and wood are lighter weight but may be top-heavy, depending on what’s planted in them. Platforms on wheels are available; these are made for setting large containers on and moving them around.

Growing mix

Choose a good, clean, lightweight potting mix. Native soil is not recommended for containers because it is too dense. Pre-bagged mixes are a good choice, and they are readily available at garden centers and nurseries.

There is no need to put a layer of gravel or anything else at the bottom of the container to “improve” drainage. Doing so actually restricts drainage, plus it leaves less potting mix volume for the roots to grow into.

Plant selection

Plant selection is the fun part, but make sure the plants chosen are suitable for the container’s location – sun, shade, etc. For advice, contact a reputable nursery or garden center, or call a University of Wyoming Cooperative Extension Service (UW CES) office. Contact information is at http://ces.uwyo.edu/Counties.asp.

Annuals – Virtually any type of annual flowering bedding plant can be grown in a container. Mix colors, sizes, and species in larger containers, with taller plants in the center or toward the back and trailing plants and vines around the outside or in front.

Perennials – Even herbaceous, flowering perennials can be grown in containers. The trick is over-wintering them – make sure they do not dry out and are protected from the worst of the elements. Choose species that do not get too large and that won’t easily spread.

Ornamental grasses – Many can be successfully grown in containers, but choose smaller, shorter species. Pennisetum (fountain grass) is a good choice, but it is not hardy and will not over-winter well in Wyoming’s climate. Other good choices are Festuca glauca (blue fescue) and Calamagrostis (reed grass).

Vegetables – Look for descriptive words like “bush,” “compact,” “dwarf,” or “determinate” as these describe varieties most suited for growing in containers. Even root crops like carrots and beets can be grown in large pots.

Herbs – Many herbs are perfect for container-growing. Some of the smaller plants, such as thyme, chives, oregano and basil, can be grown together.

Small fruits – Strawberries can be grown in containers. Strawberry pots even have holes around the sides, which allow for multiple plants. Most small fruits are perennial and will need special care during the winter.

Woody plants (shrubs or small trees) – To grow these successfully, larger containers will be needed. Also, choose plants that are naturally slow-growing and are small or dwarf in growth habit.

            If the plants grow slowly, there will be less need for pruning and repotting later. Plan on winter maintenance, including making sure containers do not dry out and are protected from the worst of Wyoming’s winter weather.

Watering

Once the plants are in the containers, watering is the most important maintenance task. If containers are small and porous, plan on watering at least twice a day, especially if the pots are in the sun. If containers are larger and more protected, less frequent watering will be needed. Drip irrigation systems specifically for containers are available.

Fertilizing

Fertilizing is easiest using a good, slow-release fertilizer. Many are on the market and, once they are applied in the spring, will last through the growing season. Alternatively, use liquid fertilizers at rates no higher than directed on the label.

Fall cleanup

            At the end of the growing season, flowering annuals and vegetables should be removed from the containers. Healthy plant material can be composted, but avoid this if there are insects or diseases present.

Reusing the potting mix from year to year is not recommended as the mix becomes compacted over time with fewer spaces for air and the root system. It may also harbor disease-causing organisms that may create problems the following year. Scrub out containers using a 10-percent solution of chlorine bleach in water.

Winter care

Perennial plants, whether herbaceous or woody, should be watered thoroughly at the end of the growing season and should be kept moist all winter. This will minimize damage to the roots from freeze/thaw cycles. Containers should be kept in a protected area, away from prevailing winds, preferably out of the sun, which will help prevent temperature extremes.

For gardeners having many containers of perennials, group them together if possible and cover them with frost fabric (a lightweight fabric available from some nurseries and garden centers), straw, or leaves to protect the plants.

Even better – if a small space is available – place the containers in a trench dug into the soil in a protected spot. Dig down almost as deep as the containers are tall, and place the containers in the trench. This will protect the root systems from winter temperature extremes. Remember to keep them moist until spring.

For more tips on container gardening, see the UW CES bulletins B-1146, Care of Flowering Potted Plants, and B-1170, Landscaping: Flowering Annuals for Wyoming, at http://ces.uwyo.edu/PUBS/Horticulture/Horticulture_Publications_Main.htm

The bulletins are also available at UW CES offices.

Contact: Robert Waggener, Editor
Phone: (307) 766-3571
E-mail: robertw@uwyo.edu

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