| Day Temperature. | Night Temperature. | |
| First week | 48°-50° F. | 41°-45° F. |
| Second week | 50°-53° F. | 45°-48° F. |
| Third week | 53°-59° F. | 48°-51° F. |
| Till flowering | 59°-64° F. | 51°-57° F. |
| Flowering period | 46°-53° F.(!) | 43°-50° F.(!) |
| After flowering | 59°-64° F. | 51°-57° F. |
| During development of stone | 53°-59° F.(!) | 48°-51° F.(!) |
| After development of stone | 61°-66° F. | 53°-59° F. |
| Ripening of fruit | 68°-70° F. | 59°-63° F. |
Not merely strong, forcing heat, but a little judicious cold, is necessary to get out the flowers and to ripen the fruit.[43]
Most flowers have very much the same general history as the cherry, but it must not be supposed that they are all alike. The differences are very interesting and curious.
Thus, for example, plants of our common Gorse, furze, or whin may be found in bloom at almost every season of the year. There are at least four seasons when there is that tremendous display of golden blossom which made the great Linnæus fall on his knees and burst into tears. These are about the 22nd March, 24th May, 15th August, and 21st November; yet there are enough odd flowers blooming in almost every month to give some cause for the saying, "The gorse is out of bloom when kissing is out of favour." The last practice, though uncleanly and dangerous, not only on general grounds, but on account of bacterial germs which may be transferred, has been authoritatively condemned in the United States, but it is still more or less popular in other countries at all seasons.
The Chickweed and some other of our annual weeds show a hardy disregard of climate. Its seeds germinate and grow at any time, so that flowers and seeds can be formed whenever there is a spell of favourable weather. Now one chickweed can produce 3000 seeds. Suppose that there are only five generations in the year, which is a very low estimate. Then one seed of chickweed might produce 3000 × 3000 × 3000 × 3000 individuals in one season!
Other plants show much the same tendency. In fine warm autumns a great many annuals bloom a second time. It is on record that forty-four spring species bloomed in one warm November. At the Cape and in other warm climates many of our annuals do not die at the end of autumn, but go on growing. They become perennial.
It is even possible to make a Tree Mignonette by pinching off the flower-buds, though this plant is usually an annual.
In fact plants are not absolutely confined to one rigid scheme, but they can alter and modify their blooming time if they find it convenient to do so. In the Mediterranean some blossom in early spring and others in late autumn, whilst in the dry, hot, and dusty summer very few flower.
In Central Africa during the dry season forest fires are by no means rare. The trees are scattered, and the ground is only covered by dried and withered grasses and sedges. One sees in the distance a rolling cloud of smoke, and soon one comes to a line of flame. It is not dangerous, not even very impressive, for a jump of three feet carries you over the flame and on to a desolate wilderness of black cinders, out of which stand up the scorched trunks and half-burnt branches of gaunt, naked trees. A day or two afterwards, bright blue and white and yellow flowers break out of those scorched branches and also from the ground.
It is difficult to understand why this happens, but certainly it is good for the flowers, which can be seen by insects from a long distance.