Altitude

The climate varies with altitude, if you live in a mountainous or hilly region you move a full hardiness zone to the north for every 1,000m(3,000ft) you climb. Elevation also effects the lenght of the growing season. Mountainside gardens are subject to drought: rainwater runs off before it can sink in. Terraced plantings will slow down the run off and absorb it. North-facing slopes receive less sunshine than south facing slopes. This can be a liability in winter, but on the other-hand it can be an advantage in mid-summer when heat sensitive plants such as alpines or ferns find the north slope more suitable. Plants may need extra shade at higher elevations. A garden on a clear day at 915m(3,000ft) above sea level will get 20 percent more sunshine ten one at sea level. If you live at a high elevation, keep plants well watered and avoid sun-sensitive species such as impatiens. But tomatoes and many other vegetables thrive in the intense sun of high altitudes. Frequent doses of organic matter(compost) greatly benefit gardens on hillsides and in mountainous regions. Keep conifer branches from breaking under the weight of heavy snow by tying them with rope. Flowering shrubs and trees which adapt in higher elevation are French hybrid lilacs, the Colorado spruce, high bush cranberries, and the hawthorn. Rosa hugonis and R.rugosa species of roses and their hybrids prosper at high altitudes. Annuals such as the cosmoses and morning glory adapt well in higher altitudes.