Garden magazines and garden supply stores are now featuring bulb advertisements and displays. Gladiolus, cannas, gloxinias, tuberous begonias, callas, amaryllis, and caladiums are just a few of the many types available.
Although they vary in their requirements, there are several basic cultural factors to keep in mind. In general, most bulbs grow best in a well-drained soil and a sunny location. The pH of the soil should run between 5.8 and 6.5. Most bulbs should be fertilized with a low-nitrate analysis fertilizer according to manufacturer’s directions on the label. If you keep these factors in mind, you should be able to produce excellent bulbous plants.
Energetic gardeners can have some bulbous crop in flower every month of the year. However, let’s concentrate on some spring flowering bulbs we can plant now.
Calla lilies can be started now and will flower during spring months. Incidentally, calla lilies are an exception to the cultural suggestions we have already mentioned. Callas will perform best in a soil that has considerable organic matter and is retentive of moisture, but not soggy. In order to obtain the best results, the clumps should be dug every three to four years and the rhizomes separated and replanted at a depth of 4 inches. Callas are at their best in cooler sections of the island like Volcano and Waimea, but they will grow in warmer sections as well.
One of the most popular bulbs to try is the amaryllis. Amaryllis bulbs can be planted any time during the winter months. Depending on the variety or hybrid grown, they will flower from February through May. The amaryllis is like most folks after the holidays. It must watch its diet. Too much food and the plant will not bloom, so it flourishes in poor soils like we tend to have in West Hawaii.
Here are a few tips to get your amaryllis to do their best. First of all, don’t tempt them with rich foods. Nitrogen-packed fertilizer makes the plant fat and green with few blooms. Like many other bulb plants, amaryllis bloom best when fed a miserly amount of a low nitrogen fertilizer. The idea is to starve the plant into worrying about next year’s blossom so that it will store food into a nice big bulb for the future blossoms, plus giving you a proud display of blooms this year. If the plants grow rampant on little or no food, try planting them in less fertile soil next time. Rationing water during the late growing stages will tend to produce better bulbs.
Bulbs planted now will put on a flower show in six to eight weeks. Select a fairly sunny spot for an amaryllis bed because too much shade will cause small flowers. Deep shade may cause the bulb to die.
Colors to choose from are red, pink, white and a combination of these colors. If you can afford them, buy hybrid bulbs. With reasonable care they will give you bigger and better blooms.
There are many other bulbs that can be planted at this time in Hawaii, including narcissus. You can also grow tulips here. Just store the bulbs at 40 degrees Fahrenheit for 60 days prior to planting and be sure to plant them immediately after removal from cold storage. Since tulips require cold weather, they have to be replaced every year or grown at elevations of 6,000 or more feet.
For more information about the culture of bulbs, ask at your local garden shop or nursery. Several gardening books are also available on the subject. University of Hawaii College of Tropical Master Gardeners can assist you as well. In Kona, the phone number is 322-4893 and in Hilo, it is 981-5199.
