Container groupings really show off your floral displays

When planting a container, mix different heights of plants for a layered effect.

Try something different from the typical tall plant in the center with a ring of shorter plants. Include plants that will cascade over the edge.

Think of your containers as large, exuberant floral displays when choosing plants. Combine different sizes of containers in each group for a good effect. A simple design of only one variety of annual planted in each container can also be beautiful.

• Pinch fall-blooming plants such as chrysanthemums and hardy asters to control their size and increase production of flowers. Pinching will encourage side branching, producing bushier, stockier plants. Make the first pinch when the plants reach 6 to 8 inches in height by removing approximately 1 inch from the tip of each shoot. Your plants have likely grown more because of the good growing conditions, so adjust your pinching height accordingly. When the resulting lateral branches reach 6 inches, pinch them as well. These plants should not be pinched later than July 4 in the Chicago area, as flower buds are formed at this time and late pinching can delay or prevent flowering.

• A number of hostas are being affected by anthracnose, which is a disease of minor concern. The anthracnose fungi cause large, irregular, white to tan spots with dark margins on the leaves. The centers of spots will often fall out, with the leaves taking on a tattered look. Entire leaves will die back when the spots grow together. The rainy weather this spring has created good conditions for this disease to develop. Anthracnose will be more prevalent in gardens that have hostas planted very close together with poor air circulation.

It is important to remove all the infected foliage on these hosta - it is early in the season and the plants should fill back in, although they may end up being smaller than normal. If possible, avoid overhead watering, though this is probably unrealistic for most gardeners. Water the hosta early in the day so that the plants will dry more quickly.

If your plants are overgrown, it may be worth the effort to space them further apart. It is OK to do that now, too.

There are fungicides available for this disease but they are not really worth the trouble for most gardeners. The fungicides will only protect new growth and not leaves that are infected, so the treatments need to be applied before symptoms appear. Mancozeb is one fungicide that can be used for this disease on hosta.

Some hostas may also have frost damage, which in some cases may look somewhat like anthracnose. Frost damage can cause jagged holes in the leaves, but will not cause as much discoloration as anthracnose. Frost can also kill sections of leaves with the leaf tissue wilting and turning brown. Simply prune off the frost-damaged leaves.

• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.