Gardening Help FAQs

Here are answers to some of the most common questions we receive about garden plants. You will find concise information on general gardening techniques as well as plant selection and care. For detailed information on specific plant pests and problems refer to our Common Garden Pests and Problems page.

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Horticulture Questions and Answers

How do I plant cannas, dahlias, gladioli and tuberous begonias?

Cannas, dahlias, gladioli, and tuberous begonias are not hardy to Missouri winters. They should be stored indoors over winter and then replanted each spring.

To give any of these plants an early bloom, start them indoors in late February to mid-March. They will respond well if planted in a well drained organic mix in shallow containers or pots. You can create your own soil mixture of peat moss and vermiculite or perlite. Cover the bulbs lightly and keep the soil damp, not wet.

Once the bulbs sprout, be sure to provide a sunny location or sufficient artificial light. Remember to turn your containers so that the plants grow symmetrically.

Cannas may be started indoors from rhizomes which are horizontal bulbous roots. These roots should be divided before planting. You will want to have firm healthy rhizomes with one or two buds for each section. Make a shallow planting that is lightly covered with soil. When the plants are about four inches tall, move them to individual pots. In May the plants can be carefully taken from their pots and planted outdoors.

If you choose to plant cannas directly into a bed outdoors, do this in early May, planting the rhizomes three or four inches deep and spacing them from one and a half to three feet apart, depending on the size of the mature plant. Be sure to improve the planting site with organic matter and fertilizer worked into the top six to twelve inches of well drained soil in a sunny location.

Dahlias need much the same attention. They may be planted indoors in March and moved outside in May, or they may be directly planted outdoors in mid-May. Remember to give dahlias a sunny well drained location. Here again, spacing will depend on the size of the mature plant.

Begonias like partial shade, but want a soil high in organic matter and a location sheltered from winds. They may be planted inside to be moved out in May or may be planted directly into a bed in mid-May. When planting, place the rounded side of the tuber down and do not cover with more than one-half inch of soil. Keep the planting medium moist.

Gladioli are usually planted directly into the ground in May and June. If plantings are made at two week intervals, plants will give more continuous blooming pleasure. Glads like sun. Planting depth will depend on type of soil and size of corm.

In general, plant deeper in sandy soil than in clay. Large corms may be planted as much as six inches deep, smaller ones about three. It is likely that you will want to provide some kind of support to keep the bloom stalks upright.