Delphiniums Growing from Seeds

Nature plants the seeds of the delphinium as soon as they are ripe. Since there are so many it makes little difference whether or not they all grow. In fact, it would be unfortunate it they did, for so many plants could never thrive so close together. This method is all right for Mother Nature, but the gardener who has to pay a high price for a very few seeds will not want to imitate Nature too closely. Take the hint that fresh seeds are better than old ones and may well believe that the seeds you plant should have a very light covering.

The best growers of delphinium seeds tell us that fresh seeds are the best, and should never be covered more than one-eighth of an inch. They also tell us that delphinium seeds must be kept moist… not wet… during the 15 to 21 days they take to germinate. Some growers like to put the seed in the refrigerator for 24 hours and then soak them in water at room temperature three or four hours before planting.

All these directions tend to emphasize the fact that the seed needs moisture if it is to germinate properly. The optimum temperature for good germination is from 50 to 60 degrees. The seeds which Nature plants wait until proper conditions exist before they start the process of germination. They germinate best in soil consisting of one part good garden loam, one part sand, and one part well rotted leaf mold. If flats are used, seeds should be planted one inch apart in rows spaced two inches apart. If seeds are sown in a cold frame, they may be broadcast if care is taken to separate the seeds widely.

Preparing the Soil

As every gardener knows, seedlings should be transplanted one or more times. If seeds have been sown too close together, the first transplanting will have to be made as soon as the seedlings have their first pair of true leaves. The second transplanting may be delayed until the plants have reached a growth of three or four inches. In any case, start preparing their permanent home as soon as the seedlings appear above ground, for their final location should be ready as soon as they are ready for it.

In the first place, the soil should be dug to a depth of at least 12 inches if drainage is good, but to a depth of 14 inches if drainage has to be improved by placing coarse sand or gravel in the bottom. Delphiniums are very sensitive to too much water, whether it is on the surface or on the roots, they also do better if their roots have access to organic matter. Leaf mold suits their taste exactly, but well rotted manure is also good.

Just after the first blooming period is over and the old bloom stalks have been cut away, and again when the new bloomstalks appear for the second blooming, they should be given a complete commercial fertilizer consisting of nitrogen, phosphate, and potash. Delphiniums are especially fond of nitrogen, so a 10-5-5 (10 parts nitrogen, 5 phosphoric acid, 5 potash) mixture should be about right. Delphiniums prefer a slightly acid soil and do not require lime unless a test shows a reaction of 6.5 or lower. Well rotted manure placed around the plants as a mulch during the summer and dug into the soil the following spring is also very beneficial.

Delphinium Troubles

As the plants grow, they should be protected from strong winds, for in ideal situations they frequently grow six feet or more with heavy bloom stalks. Many gardeners use a stake for each bloom stalk, a method which has some advantages over any other. The bloom stalk should be tied to the stake, beginning at one foot from the ground and going to within six inches of the top of the bloom.

The delphinium like other living things whether animal or vegetable, has troubles that need attention and work on the part of the gardener. Timely attention and good culture will prevent most of them, but not all. These ailments are most likely to appear in areas where soil or climate, or both, are not adapted to their needs.

Only one of the troubles I shall mention is incurable. It is a disease, or really a combination of diseases, collectively called crown rot. It is by no means confined to delphiniums. The first and surest symptom of crown rot is a progressive wilting of the stems. Good sterilization of the soil several weeks before placing your plants in it sometimes wards off trouble, but disinfecting soil is not an easy task and should be done exactly according to directions given for the material used. If a plant already has crown rot, the only thing to do is remove and destroy it. The soil in which it grew should also be permanently disposed of. If your delphiniums are placed as far as three feet apart, the danger of the disease spreading is greatly lessened.

The microscopic red spider sometimes attacks delphiniums, especially if junipers are growing nearby. Presence of this insect is shown by brownish discoloration of the leaves of the delphinium. It is easily controlled by repeated spraying malathion or Neem oil. Forceful spraying with water is sometimes sufficient if the spiders are discovered early. Delphiniums, like so many other flowering plants are sometimes bothered with aphids. Mildew, very common in some regions, has a tendency to discolor and sometimes to deform both foliage and flowers. Dusting sulfur or any of the copper fungicides will get rid of this trouble quickly.

Mulching for Winter

Those who want to grow delphiniums should not think troubles are always present or are confined to delphiniums. You have had one or more of them in your rose garden, your vegetable garden, and among your shrubs and trees. Vigilance and quick action will make their damage negligible.

Delphiniums are naturally very hardy. Although the growth above ground may completely disappear during a cold winter, the unfrozen roots will produce a luxuriant growth of flower stalks when spring comes. It is always a good idea to use coarse mulch to cover dormant plants where winters are severe or where temperatures alternate between extreme cold and periods of spring-like warmth. Take care that the mulch does not tend to smother the plants or keep them too wet.

It is difficult to say which varieties of the delphinium are easiest to grow. Of the 60 species known, less than six are used by the ordinary gardener.