There is no other garden that seems to have as many fatalities as do the plants in a rock garden. This can be a very disturbing factor for gardeners. Even with the most careful of planting and tending, there is always plants that just do not make the cut.
It is not always easy to determine what causes plants to die. Often in the spring we find many crevices and areas without plant life, and try to cover them with the use of statuary. Winter, as well as hot or wet summers, can also cause plants to fail. There are some plants that just will not make it out of their native countries, and as more data is collected, we can determine which plants do well in what localities.
Furthermore, the condition of each particular region may create differing results for rock gardens. It is common with rocks garden, that the less wanted flourish, while the sought after seem to die off. Some reasons plants may die is because they are not suited to the climate you plant them in. for example, something used to a temperate southern climate, most likely will not survive a New England winter. It is best to plant items that are hardy in your region, but this too can change each year.
Many dealers’ catalogs may suggest plants can live in certain climates, but often this is not the case. Many alpines will be killed of instantly with abundant summer rains, unless proper drainage has been provided for. The water encourages heavy growth, but quick decay of the crown of the plant soon follows. Using fertilizer results in too much growth, it is best to only use a meager diet of bone meal. To prevent against germ decay try using sand and gravel packs about the necks, steep declivities of rock face to shed rain, and poor soil to stung growth. These all work hard to keep your rock plants alive, without them your plants are much more likely to die.
Most soils are heavy wet clay which will kill your rock plants, only the hardy and touch can survive in this. It is better to create a new soil, using a peat-sand-loam mixture for all rock plants. The third cause of rock plant death is dry soil during the summer months. Cacti and Sedums can be relied on to last through the long hot summers, but the secret to keeping alpines alive is the proper construction of the rock garden. Faulty construction is sure to kill your plants during the summer.