Unless you live in Southern California, growing dazzling succulents can be a real challenge. These unique plants are largely from southern Africa, adapted mild winters and long, hot, dry summers. So what to do if you live where soils freeze and theres ubiquitous summer rain? Look up to the alpine regions of the mountains to find your solution.
Hike the Alps, the Atlas Mountains or the Rockies and youll encounter the tree line. Above this point the tree shrouded slopes transition to open rocky cliffs and landslides of rocky scree. Regular freeze thaw decomposes the rock into granules that collect in gaps and fissures. In these accumulations is little fertility, moisture or organic matter, yet many succulents are perfectly at home there.
Collectively known as alpine succulents, these super hardy plants can survive outdoors in cold climates, but only if the soils are right. Those alpine root zones are granular material so water drains through in a matter of seconds. This leaves little moisture behind to freeze in winter cold. This is important to know when creating a root zone for your alpine succulents so they can make it through winter high and dry.
The traditional way Europeans have grown these succulents is in hollowed out stone troughs. These are filled with sandy, gravelly soil that is similar in porosity to that of natural alpine ground. The troughs become a microcosm of the alpine rock garden and its succulent plants in the larger landscape.
Europeans also utilize mounds to grow alpine succulents without containers. Mounds are anchored by a few large rocks or borders, with the top layers of soil composed mostly of sharp sand and fine gravel. This is the most affordable way to get started with succulents no matter where you live.
In Britain, where daily rain is a real challenge, youll find sloping rock gardens created exclusively for alpine succulents. These are typically mounded and south facing to receive winter light and plenty of drying sun all year around. Even though they receive rain in summer, express drainage ensures it moves through without leaving much residual moisture in the root zone.
In rural England, alpine succulents are often called house leeks because they are so commonly found growing on roofs made of thatch. Straw thatch provides a root zone as porous and well drained as the rocky scree above the timber line. Folklore tells us that in times past they thought succulents warded off lightning strikes, which could turn dry thatch to a fireball in moments. This belief is due to water content in succulents, which could suppress fire in the thatch. For this same reason, succulents are ideal for wildfire resistant landscaping.
The most outstanding genera of alpine succulents are Sempervivum and Sedum species and their multitudes of named varieties. These are the best starter plants for first time succulent growers. Many of these produce bright red, blue and yellow leaf forms that offer a rainbow of color without learning a bunch of new species. Some are truly magnificent bloomers, too.
Fortunately there are two excellent books available to help you get started. Hardy Succulents (Storey Publishing, $19.95) by Rocky Mountain expert Gwen Moor Kelaidis and beautifully photographed by Saxon Holt, views cold tolerant succulents the way a designer would. Perhaps more regionally friendly and with a vastly longer text is Cacti and Succulents for Cold Climates (Timber Press, $39.95) by Colorado expert Leo J. Chance. Both of these books also cover various hardy cacti from our own western desert habitats.
The beauty of alpine succulents is their carefree nature. Once established, they can appear to be growing out of solid rock when the roots are hidden within a narrow fissure. This almost impromptu presence within stone and boulder is one of the best surprises in the garden.
This year, dive into succulents no matter where you live. Just remember to select alpine species for cooler northern states, so they rejoice in winter cold and summer rain. And above all, plant in full sun, with a porous root zone, to create conditions that make gardening with succulents a snap.