Annuals for Special Purposes

The Cool Greenhouse

Few people have facilities for growing large quantities of annuals under glass and the cultivation of such plants in pots in the cool greenhouse involves a lot of work, but it pays handsome dividends and some magnificent effects can be obtained. The remarkable exhibits of pot-grown annuals which the leading British seedsmen stage at Chelsea and other Spring Flower Shows every year are an eloquent proof of what can be done.

Seeds should be sown from August to October to provide flowering plants throughout the spring. Later sowings will, of course, prolong the flowering period. Up to the pricking-out stage the cultivation of annuals in a cool greenhouse is the same as that for the cultivation of half-hardy annuals for planting out of doors. For indoor use the young seedlings are potted either singly in small pots or, with Clarkias, Dimorphothecas, etc., several are spaced round the edge of larger pots. Immediately the pots become full of roots, plants should be repotted, and this process will have to be repeated several times until plants are finally moved into the pots in which they are to flower. These will vary in size from 5 to 12 inches, according to the type of plant.

The greatest care must be taken to ensure that the plants are not starved at any period, and applications of liquid manure will be essential. Another danger to guard against is coddling, either by keeping the temperature too high or through insufficient ventilation. To ensure the best results an entire greenhouse should be devoted to annuals, and it is not wise to try to grow them mixed up with other subjects. Much care will be necessary in watering, staking and tying. Some of the most suitable annuals for amateurs to grow as pot plants under glass are listed below:























Rock Garden

Quite apart from the question of ethics, there is an overwhelming argument in favour of using selected annuals in the rock garden. The judicious use of selected annuals can easily overcome the flowerless period of late summer, and so make the rock garden attractive for a much longer period, although the true alpine enthusiast will tell you that, provided a proper choice of alpines is made, this flowerless period need never occur. Hardy annuals are most suited for the rock garden, as they can be sown where they are to flower and may be sown in any odd place where there is room. Some will, in time, become naturalized and seed themselves in almost inaccessible positions in rock crevices. As there is less digging and weeding in a rock garden than in open ground, the chances of self-sown seedlings appearing are greater.


As climbers annuals have a particular value for they produce quick results for screening or where pergolas and trellis-work need temporary cover. The variety of plants which can be grown as climbing annuals is greater than often realized, and the following list gives the most noteworthy. They are best grown from seeds sown in small pots, and planted out when 6 to 10 inches high, as such plants will be robust enough to take hold immediately of whatever support they are going to climb on. To provide initial support small sticks can be placed in the pots, and these can be left in position when planting is done. Sweet Peas, of course, take pride of place as climbing annuals, although they have the disadvantage of requiring specially prepared positions and are not suitable for places where there is only a restricted amount of soil, such as in tubs, etc.

Probably the easiest to grow of all annual climbers is the ever popular Ipomoea purpurea (Convolvulus major) the Morning Glory, which, with its rich purple or crimson flowers and attractive leaves never fails to produce excellent results. A less common and even more beautiful convolvulus is Ipomoea tricolor (syn. I. Rubro-caerula), with blooms 4 inches in diameter and clear, sky-blue in colour, while an equally large, carmine-coloured, Continental variety is called Meraviglia scarlatto.

It should be stressed that these are not perennial in this country. They are killed by the first frosts and are not pernicious perennial weeds like the native convolvulus or bindweed, and should not be confused with it.

Although sometimes despised as being too common, Nasturtiums are still the ideal climbing annual for almost any position. They are fast growing, have attractive foliage (which is edible) and most handsome flowers. Another very lovely climber is the Canary Creeper (Tropaeolum peregrinum), with its quaintly segmented yellow flowers. Quamoella lobata or Mina lobata, as it is sometimes listed in seed catalogues, should be more widely grown, as its curious little blooms are a mixture of red, yellow and orange and always attract much attention.

Another uncommon climber is Cobaea scandens which, while it is perennial under favourable conditions, is ideal for growing as an annual. The Maurandyas are all of very great beauty.

Window-Boxes, Brackets and Hanging Baskets

The annuals used for these purposes should be of compact, semi-dwarf habit or have a tendency to hang or trail. Window-boxes must have adequate drainage provided, and if made of wood should have a metal lining. Baskets and brackets are best lined with live moss before being filled with soil. The type of soil can be similar to that used for pricking out seedlings or soilless culture methods can be employed and the plants grown in vermiculite. They are fed with a proprietary nutrient solution supplied, with full instructions for use, with the bags of vermiculite. Small, pot-grown plants are the most suitable for furnishing boxes and baskets. During hot or windy weather constant watering will be necessary, and applications of liquid manure will be advantageous. The following is a selection of plants which may be grown as annuals, and are suitable for window-box or basket cultivation.

Ageratum Linaria

Antirrhinum (dwarf)

Lobelia Aster (dwarf)




Celosia Petunia








Tropaeolum (dwarf)

03. June 2017 by admin
Categories: Chrysanthemums, Featured Articles, Plants, Shrubs, Trees | Tags: , , , | Comments Off on Annuals for Special Purposes


Get every new post delivered to your Inbox

Join other followers: