Summer flowering bulbs that are tender to weather conditions can add beauty to the home landscape if used correctly. Many have small flowers and need to be planted in groups or beds to show off their flowers. Some have large flowers and may need to be staked to be properly displayed.
There are many tuberous types of begonias available today. Traditionally, we think of the large camellia flowered types with various color combinations grown from tubers. But also available are tuberous types grown from seed by specialty growers. These seed-started types are known as ‘Nonstops’. Flowers are smaller but produced in profusion. Common to begonias is a soil mix with plenty of peat moss and perlite for good soil drainage. The tubers can be placed directly in pots or flats of a peat perlite mix and kept at 68 to 75 degrees F for sprouting to occur. Once the pink shoot starts to grow, keep plants in a sunny area. Plants should be kept evenly moist but not wet. Fertilize every two weeks avoiding fertilizers with ammonia salt sources because crinkled and curled leaves can occur. Plants can be put outside in a semi-shaded location after all frost is past. Keep plants at the same level as they were in the original container, because burying stems deeper will encourage stem rot. Stake plants at time of planting. Water weekly by applying water directly on the soil to avoid wetting leaves and flowers. Fertilize on a biweekly basis with a liquid fertilizer. Larger male or center flowers will develop if the two side female flowers are removed as plants develop. Insects problems are minimal with begonias.
Diseases that can cause problems are powdery mildew, bacterial blight, botrytis and foliar nematodes. Culturally good plant spacing, removal of dead flowers and leaves, and adequate air movement should suppress disease problems. Bulbs can be saved from year to year. Remove stems after frost has killed tops. Let tubers dry for one week then store cleaned tubers in peat moss or sawdust at 50 degrees F. Do not allow tubers to freeze.
This bright, bold-leafed tropical plant with red, pink, yellow, orange and cream flowers has gained new interest in the landscape with dwarf forms. Traditionally, canna rhizomes will produce plants from three to eight feet tall.
The rhizomes (underground stems) should be started indoors by mid-March to be placed outdoors in late May. Direct planting of the rhizome into the garden can be done in mid-May but plants can be slow to start in cool weather. The planting site should be well drained and in full sun. Amend the planting site with peat moss or compost. Space plants 18 to 24 inches apart. Water plants thoroughly after planting and fertilize as shoots emerge using 5-10-5 or 5-10-10 at the rate of three to four pounds per 100 square feet. Apply fertilizer once a month and be sure to water after application. Water plants during the summer as soil begins to dry and stake plants if necessary. Remove dead flowers to encourage more to come on the stem.
Once frost has killed the canna tops in fall, cut off the dead tops and dig rhizomes. Use care in digging. Hose off soil around rhizomes and store inside at 45 to 50 degrees F. Do not allow rhizomes to freeze.
The caladium is a bright, bold-leafed plant that is grown mainly for its foliage in both sun or shade. It produces broadly arrow-shaped leaves in striking color combinations of reds, pinks, greens, whites and bi-colors. Flowers are insignificant and can be removed when first noted. Start the potato-like tubers in early March in a peat type soil. Plant tubers in a six- to eight-inch pot, knobby side up, about two inches deep. Keep soil moist during the rooting period. It is essential to provide bottom heat of 75 to 80 degrees F to facilitate sprouting of tubers. Move plants outdoors after all frost is past to a shady, wind-protected location. Water as needed especially on hot days. In fall, dig tubers and store at 65 to 70 degrees F in peat moss. Bulbs will not tolerate cooler storage temperatures. Insects present no problem.
From July to October, this tuberous root produces two to eight foot plants with flowers 8 to 12 inches across. Seed-started cultivars flower earlier with three to five inch flowers. A wide range of colors, except blue types, are available. Tubers can be started indoors, but are generally planted directly in the garden in May in a well-drained sunny location. Plants should be staked at planting time because they will require support for the large flowers. Feed lightly at first because heavy feedings may delay flowering. Prune side stems allowing only one main stem. Aphids, spider mites, leafhoppers, stalk borers, virus and wilts can be a problem. Serious growers should stay alert to potential pests. Mulch plants after establishment to keep soil cool and preserve moisture. Tubers must be dug and stored each fall in sawdust or peat at 60 degrees F. Divide the tuber clump in spring leaving a part of the true stem attached to the tuber.
This flower is produced from a corm. Gladiolus come in a wide color range and can grow from one to five feet. Glads make excellent background plants as only one flower stalk is produced per corm. It is best to plant corms outdoors over a two month period starting in early May to stagger the bloom period. Set corms four to five inches deep and six inches apart in a well-drained sunny location. A 5-10-5 fertilizer can be used at planting time and again as the flower spike develops. Water as needed. Staking may be needed. Harvest flowers leaving a minimum of four leaves on the plant to restore the corm.
The thrip insect can pose a serious problem by damaging flower buds and stems. Consult your Extension agent for current spray recommendations.
Harvest corms in late fall. Remove the soil and old sub corm. Air dry and store in mesh bags at 35 to 40 degrees F.