The double Petunia from a small beginning, has developed into a fabulous flower that puts on a spectacular show all summer. The double varieties now available are remarkably big, and rank with some of the most beautiful subjects in the garden where, for a riotous splash of color and a glowing display, they are second to none.
As cut flowers for long lasting arrangements, double petunias are supreme. Colors are various and equally lovely arranged in a rich luxuriant mass or as points of accent with longer stemmed flowers.
Perhaps double petunias are not as easy to grow as zinnias or marigolds but they’re worth a little extra attention. Only the hybrid singles can hold a candle to them for a continuous display of rich bloom.
When they first arrived the vigor of double varieties was in question. Gardeners had the mistaken idea that doubleness was associated with weakness and slow germination. This is not true.
Most modern all-double petunias are true hybrids. Today most commercial plants are equally vigorous and the flowers are uniformly full double, large and well fringed. Such varieties are produced by crossing unrelated strains, one of which is a true-breeding small-flowered line and the other a true-breeding large-flowered line. Thus the resulting large-flowered double varieties have maximum hybrid vigor.
Many gardeners buy double petunias from specialist and, perhaps, this is more economical when only a dozen or so plants are wanted. In getting them from such sources, it’s best to deal with reputable firms that will guarantee varieties and colors specified. It is also better, when buying from garden centers to shun plants with a bloom or two already open on a tall, starved, spindly plant. Young vigorous plants are more desirable for transplanting purposes.
A discussion of varieties is outside the scope of this article but for success in growing double petunias, choice varieties are essential. Those known to produce uniformly large flowers should be chosen and mixtures should be avoided unless they are from a reliable grower.
Double petunia seed is no more difficult to germinate than any other but is more expensive. All hazards, therefore, should be eliminated so that as many seedlings come up as possible. If handled with reasonable care, a dollar packet of seed should furnish plants enough for two or three average gardens.
Because the seed is so fine, any petunia is better started in a greenhouse, hotbed or sunny window and then transplanted to a permanent location. The important thing to watch is moisture. Given a steady, regular supply of water and temperature above freezing, petunia seed will quickly germinate. The time required is controlled by the temperature. At 60 degrees, seed will germinate in slightly more than two weeks.
by C Weddle