A further basis with which to compose visually pleasing naturalistic vegetation is to use species with different cycles of growth, flowering and dormancy. Thus, there is a permanent change of seasonal aspects. In spring, wet sites need longer to warm up than dryer ones, so vegetation growth starts relatively late. It is important to use the very few early developing hydrophytes, such as Caltha palustris, Lysichiton americanus or Primula elatior. Spring bulbs for wet sites include Leucojum vernum or Fritillaria meleagris. In early and high summer, many species make an attractive display: this is the main growing period. Late summer and autumn need particular attention. Lythrum salicaria, Pontederia cordata or Allium suaveolens are examples of late flowering forbs, whilst Euphorbia palustris is very decorative with bright orange autumn-leaf colour.
Ecological strategy and competitiveness
To accomplish low-maintenance-plantings, it is necessary to combine species of similar competitiveness according to the fertility of the site. Fertile sites should be planted with ‘C-Strategists’
In a pond with a tiered profile it is possible to have a sharp transition from the swamp and shallow-water zone to the Water Lily zone
(competitiors) that produce a dense cover. In depth zones 3 and 4 (see section ‘Vegetation zones’), this will mean reed-forming plants. In zone 2, vigorous tall forbs (Filipendula ulmaria) and rhizomatous species (Carex acuta) are able to form durable communities needing virtually no maintenance. During the first few years of development, shortlived ruderal plants, such as Lychnis flos-cuculi, and Mimulus luteus, form a dense cover until they are eventually overgrown by competitor species.
Artificially sealed water bodies with a poor substrate tend to become very low in nutrients. This is desirable for guaranteeing clear water conditions. In zones 3-5, plants from richer native sites are suitable, especially when some water movement exists. Even Water Lilies or other floating leafed plants develop satisfactorily after a certain period of slow growth. In zone 2, however, plants from rich wet meadows mostly react with symptoms of deficiency. This area is ideal to establish bog or fen vegetation with stresstolerators: small, slowly growing species that tend to occur naturally on sites poor in resources. Unfortunately, these plants are rarely to be found in the nursery ranges of swamp plants.