Land of the giants

We look at a range of large herbaceous plants suitable for the small garden

TO make the best use of available space, the usual advice is to plant small trees and shrubs and low-growing subjects in ‘mini’ borders. While small plants are ideal for small plots, it is surprising what an improvement can be effected by the strategic placing of a giant or two, if only to give some weight and height while the trees and shrubs are growing. Many giants can be used for this purpose, of which only a few can be mentioned here. Though none needs staking, most have large leaves that may be damaged or broken if grown in exposed situations.

A giant biennial with the in-built ability to fight back is the cotton thistle, Onopordum acanthium, for the long beautifully flounced leaves and stiffly branching flower stems are armed with needle-sharp spines. Easy to grow from seed, the onopordum spends its first year building a magnificent rosette of large silver leaves from which arises the following summer a 6-8ft (1.8-2.4m) stem, well branched with purple thistle flowers. The seeds will germinate freely, so it is best to remove the heads before too many fall. An architectural plant, it is at its best against a dark background.