Supporting Perennial Plants
There is a misconception that herbaceous plants must be both sheltered and staked. This is not always the case: bear in mind that gardens full of movement are more dynamic and interesting: while woody plants will not bend much in the breeze, flowers and grasses will billow attractively. Many tall plants are self-supporting, including foxgloves (Digitalis), mulleins (Verbascum), and Verbena bonariensis. Choose carefully, and you can grow a range of plants even in fairly windy sites—they often develop sturdier stems, more resistant to wind damage. Plants grown in a sheltered spot are more likely to suffer in a sudden blast of wind than those that are exposed all season long.
That said, you may want to grow some herbaceous plants with delicate or weak stems, which are prone to splay out due to the weight of their flowerheads or when beaten down by strong wind or rain. In exposed areas, supports are almost always necessary; insert them in spring, when leafy growth begins, as plants that have flopped never recover their former glory. Provided the support is a little shorter than the eventual height of the plant, it will soon be hidden by the foliage (though remember that some materials actually have a charm of their own).
Choosing Suitable Supports
A clump of bamboo thinned annually will yield a good supply of canes to be used as supports. Cut when young, the stems will be pliable enough to bend into hoops and semicircles. If you have space, you could also grow a hazel or willow to provide a supply of twiggy stems and thicker stakes for building rustic tripods.
Canes and pea sticks will be adequate for many perennials. You can lift plants that have flopped with canes and string, but if you bunch the stems tightly, they could look worse than before. For large-flowered, tall plants, such as dahlias, peonies, and chrysanthemums, supports that allow the stems to grow through them are more effective. Metal grids on long spikes can be raised as the plants grow. For very tall dahlias and delphiniums, tie each stem to a sturdy single stake using garden string or raffia.
Where a border flanks a path or lawn, hold plants back with metal or wooden-log edging, or make your own from freshly cut bamboo canes bent into arcs. Several of these can be used to form a low temporary fence or to keep bushy growth in check, preventing it from swamping lower plants.