Why some flowers sit close to the ground
Why low flowers are common above the treeline and how their position affects warmth and wind exposure.
Above the treeline, the flowers that last through the cold are mostly the ones that sit close to the ground. This note explains why, and what a reader can check on a slope to see the effect of height and wind.
Why height matters
Air near the ground is warmer on a calm, sunny day than air a metre above it. Bare stone and bare soil absorb sunlight and release heat slowly after dark. A plant only a few centimetres tall stays inside that layer of warmer air. The treeline marks the height above which trees cannot grow tall enough to keep their shoots clear of the cold and the wind.
Wind is the second factor. It draws heat from leaves and stems, and it dries exposed tissue. Gusts also drive grit and ice crystals against anything standing upright. A low plant offers less surface to the wind and often gains shelter from rock or from its neighbours.
What a low position looks like
- Stems that lie flat or form a dense mat, with few upright shoots
- Leaves packed close at the base, often small and thick
- Flowers held just above the leaves, rarely on tall stalks
- Thickest growth in hollows and on the sheltered side of rocks
These signs are not proof on their own. A sheltered hollow may hold taller grass, and a windy ridge may hold a plant that stays low because of thin soil. Look for several signs together.
- Microclimate
- The local conditions of warmth, moisture and wind in a small space, such as the few centimetres of air above a stone.
- Leeward
- The side of an object or slope that faces away from the wind.
- Exposure
- How fully a place or plant is open to wind, sun and cold.
- Treeline
- The upper limit on a mountain where trees still grow, though in stunted or bent form.
Checking a slope
- Choose one slope and note the direction it faces.
- Find a rock or hollow with a plant growing on its sheltered side.
- Compare the plant's height with a plant on the open ridge nearby.
- Record the height in centimetres, and the wind direction as shown by flattened growth or bent stems.
Record what you see without picking anything. A photograph with a scale object, such as a pencil or a small ruler, shows size. A simple sketch of the plant's outline, with a written note of the slope and its direction, is enough for a field record. For the shapes named here, see cushions, mats and rosettes. For the conditions behind them, see how high ground shapes the plants.
For cushions and mats, see telling a cushion plant from a mat plant. For leaves arranged at the base, see reading the leaf rosette. For flower timing across a slope, see reading flowers and seasons on the slope.