After the rockwork is complete and the garden water features are installed, you can forget about those areas, and focus on planning your garden. There are three sizes of rock plants that relate to time and placement of pockets. There are smaller shrubs or large field grown herbs, like Moss Phlox or Megasea Saxifrage, that are best planted when the rocks are laid in place.
The roots of the plants should be spread out and drawn back, the soil added, and the next rock should be laid. When working in this manner you will not be able to plant later. This allows for immediate results. With proper watering in the summer and peat moss in the first winter, the planter will grow and thrive for the next season.
For crevices of cliffs the best time to plant is during construction. Major planting should be done several months several months after construction. The first year of a rock plant is best spent in a special nursery.
You can start your rock plants from seeds, cuttings divisions, or from a nursery. Seedlings, Root cuttings, and divisions need to be planted in smaller pots that are not over two inches across and set closely in a cold frame.
This needs to be done in the early summer during the construction of your garden, that way growth will be better than a newly finished rock garden. After a winter under dry leaves, each plant can be set directly in place and will start to bloom and grow.
Dealers offer these pot plants for you to buy, but you can save time and work by growing your own from seeds and setting them wherever you wish. You can also try to plant the seeds directly into the place during the spring, and after plants have been set out, choose the seeds that are best for germination.
In a favorable season there may be good results, but usually the weediest survive. You will get better results from expensive seeds by the previous method, and the sure - to-grow are really too certain to self sow and become weeds of little value. Examples are Silene drummondii, Alyssum incanutn, Silene viridiflora, and Lotus tenuis.
They are no better than Chickweed and Shepherd's Purse, though offered as good rock plants. A very sad experiment is the sowing of seed of easy small annuals for immediate effect the first year. After the first year they will be present for many years; and pulling out Portulaca, Sweet Alyssum, and Catchfly for many seasons is a punishment greater than the crime.