Growing rock plants from seed is a tricky business; in fact, it is among the most difficult of all gardener’s tasks!
Alpine seed is different from that other plants in two important ways.
It needs to be frozen in winter to germinate, and germination, with some species, takes a long time — sometimes as much as two or three years.
Growing Rock Plants From Seeds
Nevertheless, rock plants are expensive to buy. If only a small proportion of the seed germinates, the resulting plants’ worth anything from nine pence to five shillings a plant (and considerably more in America) will repay the time and trouble taken.
The best plan is to attack along three lines. First, divide the seed chosen into three equal piles. The first should be broadcast on the rockery.
The seed will need well-drained soil and, to begin with, a shaded aspect.
As it must lay there for, possibly, a year or two before it comes up, care must be taken to plant it where it will not get dug over as time goes on.
Where To Plant It
Quite the best place is on the shady side of deciduous shrubs such as azaleas, berberis, and others.
Here it will receive the shade it requires until the first pair of true leaves appear, and it will remain undisturbed as long as the shrub grows. Another good place is among small carpeting plants in a shady spot.
The carpenter should not be of so close a growth that nothing will ever grow among it; cotula, acaena, and sagina are quite useful, and other suitable plants will be learned with experience.
Autumn Planting Of Seeds
The second batch of seeds should be planted in the Autumn as soon as space is available. It should be sown in boxes of sandy soil plunged to the rims in a bed of ashes.
Drainage is all important as the slightest excess of moisture will rot all the choicer seeds.
If a bed of ashes is not available, the seed can be sown in a shaded border, but care must be taken to see that this is as well drained as possible.
The seed itself should be sown in a ridge of pure sand placed upon the surface of the soil, and care should be taken to leave ample space for the clothes, which are an important aid to success.
Alpine seed is, of course, very fine. It should be mixed with fine sand for ease of handling.
In its natural state, the alpine seed lies dormant under a blanket of snow throughout the winter.
Imitating Conditions For Germination
Under the snow, it is both warm and dry, and it is these conditions that we must strive to imitate if the seed is to germinate successfully.
In this respect, the use of glass is of great assistance. The situation is ideal if the seed is sown in boxes or pots and a cold frame is available. If not, and the seed is sown in the open, we have recourse to cloches.
It is necessary to cover the glass in a sonic way until germination, as most alpines (there are a few exceptions) grow better in the dark.
Achieve Whitewash Color
The best way to achieve this is to whitewash with “green whitewash” (i.e., either green distemper or whitewash, which has been rendered dark green by adding sufficient colon ringmaster).
This coating should remain on the glass until germination, when it should be removed permanently.
If cloches are used, they should be as small as possible and should be treated in the same way.
With both frame and cloches, great skill is needed during the Winter to manipulate them so that the seed makes the most of weather conditions.
This means that when rain is likely, the glass must be kept on, but if frost or rain is about, it must be removed.
But it is not always easy to tell. If a mistake has been made, it must be remedied as soon as possible, which usually means a job in the rain or snow.
Snow is so beneficial that none of it must be wasted. As long as the seeds are covered with snow, they should be left well alone.
As soon as the seed has germinated, it will need all the light it can get. For this reason, the plants should be planted out in an open position as soon as they have developed their first pair of true leaves.
Under Glass
Small plants should be kept under glass until summer arrives and need not be moved to their permanent quarters until the following Autumn.
The length of time taken in germination should be borne in mind, and no soil containing alpine seed should be thrown away until there is no possible hope of its germination.
Even in this case, it is best to empty it onto the rockery where, as has happened in my own case, plants of the seed in question may be found growing long after the seed has been forgotten.
44659 by Bissett Lovelock