This section is from "The Horticulturist, And Journal Of Rural Art And Rural Taste", by P. Barry, A. J. Downing, J. Jay Smith, Peter B. Mead, F. W. Woodward, Henry T. Williams. Also available from Amazon: Horticulturist and Journal of Rural Art and Rural Taste.
The season having now arrived for planting out many of the plants stored in the house for the winter season, the remaining plants can be thinned and others grown on for summer decoration. It is a mistake to cram as many plants into a house as will stand, at any time; but in the most extensive houses we generally find ourselves crowded during the winter and spring; this is more especially the case when houses are limited; but there is no excuse for over-crowding in the summer, for a few well-grown plants will give much more pleasure than a house full of awkward plants.
Such plants as myrtles, diosmas, heaths and acacias, are best placed in a shaded spot, protected from wind, but not under drip from trees, with bricks or coal ashes under pots to prevent worms entering. It is best to take a dull, damp day for this work, the plants are then not so likely to suffer from the change, and for a few nights previous there should be air, in the house continually. These plants are usually best outside, after the middle of May. Camellias, in pots, are also best outside, after the buds are set, which is usually later in the season; if these plants do not flower as early as desirable, now is the time to force them by giving a brisk heat and plenty of moisture. It is surprising how quick the growth is complete and the buds formed. After this the plants are best outside, for the summer.
Azaleas it is best to keep inside if there is spare room; the plants are more under command, but if turned out they require strict attention in watering, often requiring it several times in a day; and care must be taken that there are no weeds and rubbish at hand; this is usually a first rate nursery for thrip and red spider, which often does much mischief before noticed; but with attention to these points, plants required to make but one growth in a season, are as well outside as in, if room is scarce after the buds are set; but young plants which are required to make specimens in as short time as possible, should be grown in-doors, with plenty of heat and moisture, the shoots kept stopped, and the second growth will flower as well as the first.