Sowing seeds of success

At this time of year many perennial plants have to solve a problem. They produce seeds but if they just drop them on the ground the young plants won’t flourish because of competition from their parents. They have evolved a variety of strategies to solve this problem.

Many wild plants use wind to disperse their seeds. Obvious examples are dandelions and thistles. They produce large quantities of tiny seeds, each one equipped with its own fluffy ‘parachute’. Under ideal circumstances these seeds can travel up to 1,000km. Sycamore and ash trees produce larger seeds which have wings rather than parachutes and these can fly for up to about 180m. Pine cones are not very aerodynamic but can be blown surprising distances in winter winds.

Many plants use animals, birds and insects to disperse their seed. Some, like brambles or hawthorn trees, produce fruit. When the fruit is eaten the animal or bird either spits out the seed or, more commonly, it passes through their digestive tract and is expelled in droppings. Ants collect the seeds of wood anemones and bring them home to feed their larvae. Some trees, like oaks and hazels, produce large seeds which don’t have a fruit coating but are themselves nutritious. Birds like jays and animals like squirrels will collect these and store them for the winter, often by burying them. Not all nuts and acorns are recovered and some will germinate.