Bulbs and Tubers
It is customary to write of bulbs and tubers together, because the tops and flowers of all the bulbous and tuberous plants spring from large reservoirs of stored food, giving rise to similar methods of culture and of storage.Structurally, the bulb is very different from the tuber, however. A bulb is practically a large dormant bud, the scales representing the leaves, and the embryo stem lying in the center. Bulbs are condensed plants in storage. The tuber, on the other hand, is a solid body, with buds arising from it. Some tubers represent thickened stems, as the Irish potato, and some thickened roots, as probably the sweet-potato, and some both stem and root, as the turnip, parsnip, and beet. Some tubers are very bulb-like in appearance, as the corms of crocus and gladiolus.
Using the word "bulb" in the gardener's sense to include all these plants as a cultural group, we may throw them into two classes: the hardy kinds, to be planted in fall; and the tender kinds, to be planted in spring.
_Fall-planted bulbs._
The fall-planted bulbs are of two groups: the "Holland bulbs" or early spring bloomers, as crocus, tulip , hyacinth , narcissus, squill, snowdrop; the summer bloomers, and as lilies. The treatments of the two groups are so similar that they may be discussed together.
All these bulbs may be planted as soon as they are mature; but in practice they are kept till late September or October before they are put into the ground, as nothing is gained by earlier planting, and, moreover, the ground is usually not ready to receive them until some other crop is removed.
These bulbs are planted in the fall (1) because they keep better in the ground than when stored; (2) because they will take root in fall and winter and be ready for the first warmth of spring; (3) and because it is usually impossible to get on the ground early enough in spring to plant them with much hope of success for that season.
The bulbs lie dormant until spring, so far as outward appearances go; they are mulched to insure that they will not start in warm weather of fall or winter, and to protect the ground from heaving.
To secure good bulbs and of the desired varieties, the order should be placed in spring or early summer. For flower-garden effects, the large and mature bulbs should be secured; for colonizing in shrubbery or on the lawn, the smaller sizes may be sufficient. Insist that your bulbs shall be first class, for there is wide difference in the quality; even with the best of treatment, good results cannot be secured from poor bulbs.
It is not generally known that there are autumn-flowering bulbs. Several species of crocus bloom in the fall, _C. sativus_ (the saffron crocus) and _C. speciosus_ being the ones generally recommended. The colchicums are excellent autumn-blooming bulbs and should be more generally planted. _C. autumnale,_ rosy purple, is the usual species. These autumn-blooming bulbs are planted in August or early September and treated in general the same as other similar bulbs. The colchicums usually remain in the ground several years in good condition.
All kinds of bulbs are partial to a deep, rich, water-free soil. This is no small part of their successful culture. The spot should be well drained, either naturally or artificially. In flattish and rather moist lands the beds may be made above the surface, some 18 inches high, and bordered with grass. A layer of rough stones a foot deep is sometimes used in the bottom of ordinary beds for drainage, and with good results, when other methods are not convenient, and when there is fear that the bed may become too wet. If the place is likely to be rather wet, place a large handful of sand where the bulb is to go and set the bulb on it. This will keep the water from standing around the bulb. Very good results may be had in heavy soil by this method.
The soil for bulbs should be well enriched with old manure. Fresh manure should never be allowed close about the bulb. The addition of leafmold and a little sand also improves the texture of heavy soils. For lilies the leafmold may be omitted. Let the spading be at least a foot deep. Eighteen inches will be none too deep for lilies. To make a bulb bed, throw out the top earth to the depth of 6 inches. Put into the bottom of the bed about 2 inches of well-rotted manure and spade it into the soil. Throw back half of the top soil, level it off nicely, set the bulbs firmly on this bed, and then cover them with the remainder of the earth; in this way one will have the bulbs from 3 to 4 inches below the surface, and they will all be of uniform depth and will give uniform results if the bulbs themselves are well graded. The "design" bed may be worked out easily in this way, for all the bulbs are fully exposed after they are placed, and they are all covered at once.
Of course, it is not necessary that the home gardener go to the trouble of removing the earth and replacing it if he merely wants good blooms; but if he wants a good bed as a whole, or a mass effect, he should take this pains. In the shrubberies and on the lawn he may "stick them in" here and there, seeing that the top of the bulb is 3 to 6 inches beneath the surface, the depth depending on the size of the bulb (the bigger and stronger the bulb, the deeper it may go) and on the nature of the soil (they may go deeper in sand than in hard clay).
As the time of severe winter freezing approaches, the bed should receive a mulch of leaves, manure or litter, to the depth of 4 inches or more, according to the latitude and the kind of material. If leaves are used, 3 inches will be enough, because the leaves lie close together and may smother out the frost that is in the ground and let the bulbs start. It will be well to let the mulch extend 1 foot or more beyond the margins of the bed. When cold weather is past, half of the mulch should be removed. The remainder may be left on till there is no longer danger of frost. On removing the last of the mulch, lightly work over the surface among the bulbs with a thrust-hoe.
If the weather happens to be very bright during the blooming season, the duration of the flowers may be prolonged by light shading--as with muslin, or slats placed above the beds. If planted where they have partial shade from surrounding trees or shrubbery, the beds will not need attention of this kind.
Lilies may remain undisturbed for years. Crocuses and tulips may stand two years, but hyacinths should be taken up each year and replanted; tulips also will be better for the same treatment. Narcissus may remain for some years, or until they show signs of running out.
Bulbs that are to be taken up should be left in the ground till the foliage turns yellow, or dies down naturally. This gives the bulbs a chance to ripen. Cutting off the foliage and digging too early is a not uncommon and serious mistake. Bulbs that have been planted in places that are wanted for summer bedding plants may be dug with the foliage on and heeled-in under a tree, or along a fence, to stand till ripened. The plant should be injured as little as possible, as the foliage of this year makes the flowers of the next. When the foliage has turned yellow or died down, the bulbs--after cleaning, and curing them for a few hours in the sun--may be stored in the cellar or other cool, dry place, to await fall planting. Bulbs that are lifted prematurely in this way should be planted permanently in the borders, for they will not make good flower-garden subjects the following year. In fact, it is usually best to buy fresh, strong bulbs each year of tulips, hyacinths, and crocuses if the best results are desired, using the old bulbs for shrubberies and mixed borders.
Crocuses and squills are often planted in the lawn. It is not to be expected that they will last more than two to three years, however, even if care is taken not to cut the tops closely when the lawn is cut. The narcissus (including daffodils and jonquils) will remain in good condition for years in grassy parts of the place, if the tops are allowed to mature.
_List of outdoor fall-planted bulbs for the North._
Crocus.
Hyacinth.
Tulip.
Narcissus (including daffodil and jonquil).
Scilla, or squill.
Snowdrop _(Galanthus)._
Snowflake _(Leucoium)._
Chionodoxa.
Hardy alliums.
Bulbocodium.
Camassia.
Lily-of-the-valley.
Winter aconite (_Eranthis hycmalis_).
Dog-tooth violets (_Erythronium_).
Crown imperial (_Fritillaria Imperialis_).
Fritillary (_Fritillaria Mekagris_).
Trilliums.
Lilies.
Peonies, tuberous anemones, tuberous buttercups, iris, bleeding heart, and the like, may be planted in autumn and are often classed with fall-planted bulbs.
_Winter bulbs_
Some of these bulbs may be made to bloom in the greenhouse, window-garden,
or living room in winter. Hyacinths are particularly useful for this purpose,
because the bloom is less affected by cloudy weather than that of tulips
and crocuses. Some kinds of narcissus also "force" well, particularly the
daffodil; and the Paper-white and "Chinese sacred lily" are practically
the only common bulbs from which the home gardener may expect good bloom
before Christmas. The method of handling bulbs for winter bloom is described
under Window-gardening
_Summer bulbs._
There is nothing special to be said of the culture of the so-called summer-blooming and spring-planted bulbs, as a class. They are tender, and are therefore planted after cold weather is past. For early bloom, they may be started indoors. Of course, any list of spring-planted bulbs is relative to the climate, for what may be planted in spring in New York perhaps may be planted in the fall in Georgia.
The common "summer bulbs" are:--
Gladiolus
Tuberose
Dahlia
Canna
Arum
Calla
Calochortus
Alstremeria
Amaryllis
Colocasia