MAINTAINING A ROCK GARDEN
Once established, rock gardens usually need to be regularly weeded, fed at intervals and watered whenever the soil becomes dry. Plants should be kept tidy and cleared of any dead flowers or leaves, and checked regularly for signs of pest infestation and disease. Top-dressings should be replenished every year to reduce evaporation of water from the soil and to suppress weed growth. In cold or wet winters, some plants may need some additional protection.
Watering: Once established, most alpines and rock garden plants will not need any additional watering unless the weather is very dry. Check the soil – if it is dry at a depth of 3-5 cm (1¼-2in), water thoroughly until the soil is moist. Soak the area occasionally in early mornings or late evenings, rather than applying frequent small amounts of water. Never water in frosty weather; The soil in troughs will tend to dry out more quickly than in rock gardens; hand water each plant individually so that it receives the right amount of water. Feeding: If you used a good compost with slow-release fertilizer when planting, you should not need to feed the area for several years. However, once growth slows down and flowers become more sparse, scratch in a mixture of slow-release fertilizer and bone meal around the plants each spring; You will need to replace pockets of soil every few years if vigorous plants are grown in them, or when replanting. Weeding: To minimise weeds during the first few years, always use sterilised compost when planting. Remove any weeds that do appear immediately so that they do not have chance to flower or set seed. Most weeds may be removed using a three-pronged cultivator which will also loosen and aerate the soil. You may need to use a translocated weedkiller to eradicate established perennial weeds. Top-Dressing: The top-dressing applied to alpines and rock garden plants depends on the species of plant grown, but in general, it should complement the stones used within the planting areas. Stone chippings or coarse grit are suitable for most situations, however, never use limestone chippings around lime-hating plants; Renew the top-dressing when necessary, topping up whenever bare patches appear. Make a thorough check in late autumn to ensure good soil coverage for the winter, then re-check in spring. Winter Protection: Alpine plants may need additional protection in the winter – not necessarily from the cold, but from the damp. This is especially true of cushion plants, and those with hairy leaves. Cover troughs with a pane of glass or Perspex, propped with bricks to ensure that the air circulation around the plants is not restricted. Weigh this down with another brick or stone. `