This is the chief month for bedding, and the crowded state of pits and houses creates a natural anxiety to push forward the work; yet the exercise of a little patience may save many a valuable lot of plants from being injured past recovery. Although the days are long, and perhaps sunny, the nights are often treacherous, especially in the early part of the month. The first business is to prepare the plants gradually for transfer to the open ground by free exposure whenever there is a favourable opportunity. Take off the lights on genial days, and by degrees open them at night, until they can be dispensed with altogether. About the second week of the month it will generally be safe to put the most hardy subjects on a bed of ashes, under the shelter of a hedge or wall, before planting them. Begin with Antirrhinum, Dianthus, Phlox Drummondii, Stock, and Verbena. A little later on, others which are rather more delicate, as, for instance, Balsam, Begonia, Dahlia, Petunia, Zinnia, &c., can be treated in the same way, until the great bulk of them are in final quarters. Sub-tropical plants, such as Nicotiana, Ricinus, Solanum, and Wigandia, had better be kept under control till the first or second week of June.
Annuals.—There is still an opportunity of sowing many varieties, and also to make further sowings of others that are already showing signs of promise. The practice of insuring a succession of all flowers much in demand for vases, of which Sweet Peas are an example, is on the increase, and deserves to be further extended. Another point is that many annuals which require heat in earlier months may with confidence be sown during May in the open ground.
Hardy Biennials and Perennials.—Seed of many favourite biennials and perennials may be safely sown in the open ground during May, June, and July, and as a general rule the finest plants for flowering in the following season are obtained from the earliest sowings. The bed for the seed should be prepared with care and a friable loam is the best for the purpose. Immediately the seedlings are large enough to handle, transplant to small rich nursery beds and shift to flowering positions in the autumn. A number of these subjects are dealt with individually in the calendars for the months named, and others which are suitable for the purpose are:
Anchusa italica
Aster sub-cæruleus
Aubrietia
Candytuft (Iberis)
Cheiranthus Allionii
Chrysanthemum leucanthemum
Coreopsis grandiflora
Cynoglossum
Digitalis
Gaillardia
Galega officinalis
Gaura Lindheimeri
Geum
Gypsophila paniculata
Heuchera
Lupinus
Cenothera
Poppy, perennial
Pyrethrum
Saxifrage
Thalictrum
Verbascum
Viola
Antirrhinum is admirably adapted for a dry and sunny position, in which it will thrive and flower freely.
Balsam.—Towards the middle of the month a final sowing may be made with safety in the open ground. Former seedlings will need potting on until they reach the eight-inch size, and at each transfer put the plants in rather deeper than before; this encourages the growth of roots from the stems. While increasing the pot-room not a bud will show; but immediately the roots are checked by the pots, flowering will commence. The old method of stopping and disbudding not only spoiled the plants, but robbed them of the finest flowers, which are invariably produced on the main stem. Since the natural method of growing Balsams has been in favour it is usual to see grand specimens covered with immense flowers.
Campanula.—The hardy perennial varieties may be sown in the open during the present month to provide seedlings for transplanting to flowering positions in autumn. Should there be any good reason for delay it will not be too late to sow in June or July, but the finest specimens are generally produced from May sowings. The best results can always be obtained by raising the required number annually and discarding the plants after they have flowered in the following season.
Cineraria.—Those who care to have Cinerarias in bloom during November and December may do so from a sowing made at the beginning of April, but it is not usual to start so early. Our own practice is to sow twice, during the present month and again in June, to insure a succession. From this month’s sowings we look for our finest plants. The Cineraria is easy to raise and to grow, but it will by no means take care of itself. It has so many enemies that unusual vigilance is necessary to flower it to perfection. It thrives in a compost of turfy loam, with a little leaf-mould added; but the soil should not be over-rich, or there will be much foliage and few flowers. Still, as the plant is a rapid grower, it must not be starved, neither must it suffer for lack of water. Pots or pans may be employed for the seed; and as the young plants grow freely, they may go straight to thumb pots without the usual intermediate stage of pricking off.
Coleus should be finally shifted into 48-sized pots. If signs of decline become manifest, weak liquid manure water given occasionally will revive the plants and intensify their colours. During the summer any ordinary greenhouse or conservatory will suit them, provided they are shaded from fierce sunshine.
Cyclamen.—The strongest seedlings should now be ready for 60-sized pots. Abundant but judicious ventilation, plenty of water, and freedom from aphis, are the conditions to be secured.