Archive for January, 2008

Gloxinias grow best in porous soil. I use equal parts of leafmold or peatmoss and sandy soil with a 6-inch pot of processed cow or sheep manure for each bushel. Before planting, soak tubers

68. Rechsteineria cardinalis, with emerald green, soft leaves and flashy

red flowers, appeals equally to novice house plant gardeners and gesneriad connoisseurs. (Photograph by Author)

in a 1-200 solution of Carco-X or other fungicide. Apply the same solution to the potting soil of tubers, cuttings, seedlings or seed, and wait about two days before planting. Subsequent applications direct to moistened soil in the pots of growing gloxinias will keep them free of common troubles.

Start fertilizing as soon as you see flower buds, and continue at biweekly intervals until the plant reaches its peak of bloom. Use a fertilizer which contains the minor or trace elements (boron, manganese, etc.). If these are not present in the brand you are using, switch to another, or buy packaged trace elements and apply them in conjunction with the major-element fertilizer.

The newer hybrid forms appeal most to collectors. Flowers are wide-throated, open-faced, in a great array of colors. Although no yellow gloxinia has been developed, there are a number with yellow throats, and there is plenty of variety with which to stock your greenhouse. I know of only a few firms selling doubles, so if you discover any among your seedlings, it would pay you to reproduce them.

Popular with collectors are the species. These have downward-facing, slipper-type flowers and pouchlike corollas. Sinnin-gia speciosa, the blue slipper and its varieties, have fair sized slipper-type flowers in blue, purple, white, and rose, and plain green leaves. S. macrophylla, commonly called Brazilian gloxinia, has olive-green leaves red beneath and nodding purple flowers; regina is similar; S. eumorpha displays dangling white bells among shiny green leaves. Baby of them all is S. pusilla with leaves scarcely an inch long and tiny quarter-inch blue-purple flowers. The largest of the species, S. tubiflora, has

66. Achimenes is another favorite gesneriad. The “catkins” visible in both

leaf axils of this rooted cutting are rhizomes, valuable for propagation.

(Photograph by Taylor; courtesy, National Horticultural Magazine)

67. This photo of Smithiantha rhizomes shows why gesneriads are outstanding crops for the budget-wise grower. Each rhizome (background) can be divided into innumerable scales (foreground), and every scale acts as a seed to produce a new plant. (Courtesy, Horticulture)

pointed silvery-green leaves and fragrant white flowers resembling nicotiana.

Schedule for Tubers

If you are starting with tubers, plant them in February for June to July flowers and give a daytime temperature of 70 to 80 degrees with the usual 10-degree drop at night. Start tubers in any light soil, peatmoss, sphagnum moss, or vermiculite. As soon as they show growth, move to 4-inch pots. For maximum flowering, they require subsequent shifts to 5- or 6-inchers, depending on size of tuber.