Shortly after the planting of the desired species, maintenance commences. As the sown and planted species start growing, so do the unwanted species, in quite a range: Poa annua, Cardamine hirsuta, Cerastium fontanum spp. vulgare, Cardamine pratensis, Epilobium species and Ranunculus repens are but a few examples. As soon as they can be recognised, they are removed by weeding them out.
Weeding always causes some disturbance of the soil. One should therefore try to perform it in a manner that causes the least disturbance possible. The smaller the plants that one is weeding out, the better: this way the soil surface is least disturbed. In any case, one should take care to remove unwanted species—and unwanted individuals of desired species!—before they go to seed. This way one can make sure the workload does not get out of hand.
Meanwhile, the desired species are developing well, they are spreading out and increasingly occupying the open spaces. Their seeds will provide offspring, so as to cover all open spaces after a period of one to three years. In addition to weeding, maintenance consists of cutting and carrying off wilted and dead parts of the plants, collecting leaves that have been blown into the area, and distributing seeds of desired species at the spots one would like them to establish themselves in. One may transplant seedlings to more favourable spots and spread seeds of suitable new species that one expects to be successful. In the meantime, the vegetation starts closing and development continues. Certain species are becoming intrusive through self-seeding and strong growth, they will occupy more and more space, thus oppressing the slower or weaker species. In such cases, the hand of the manager will correct, lead and guide their development.
Whenever one needs to enter and tread on the vegetation, this needs to be done with the utmost care. It is essential to create as little disturbance and damage as possible. It follows that in rainy, wet periods it is preferable to stay out of the vegetations: treading on the soil will compact it and damage the soil structure. All maintenance activities are performed unobtrusively, making it seem to the visitor that there is no maintenance at all, as if it is all spontaneous development. In such a way one can have intact vegetation giving a strong, intense expression of naturalism. It also allows the spontaneous establishment of all kinds of mosses, their spores, leaflets and gemmae being introduced by the wind. Consistent weeding management may result in splendid moss vegetations, which create a supporting tapestry, lending a naturalistic image to the whole. In addition, it creates a favourable germination substratum for species such as orchids and helps tender species like Wahlenbergia to survive the winters.
On moist, often acidic soils, one may also see the spontaneous development of a plant with mosslike features: Sagina procumbens. In spots, it may grow into an attractive, evenly green soil-cover. Only where it becomes too thick, tending to suffocate everything else, should one keep it at bay.
Where the examples mentioned previously concern perennials only, one can also use vegetation composed of annuals and biennials to great effect. Ornopordon acanthium and Isatis tinctoria, Melilotus species, Oenothera species, Reseda luteola, Echium vulgare, Verbascum species, Dipsacus sylvestris, Arctium tomentosum, Centaurea cyanus, Agrostemma githago and Papaver species are some examples. They often have a ruderal character and require a relatively rich, sunny and dry, preferably calcicolous, habitat. Besides the weeding out of unwanted species, its management consists of keeping the soil open by intermittent digging, disturbing and, when necessary, additional sowing. Each species is sown on the ‘spot of its own’ that one has determined beforehand. In a later phase, when it has started self-seeding, one can, if one wishes, let more naturalistic patterns and compositions take shape. The guiding hand of the manager, here restraining and there stimulating developments, is the invisible means of control. In this manner, one can avoid the over-domination of strong over weak species, resulting in a more exciting vegetation.
Dead flower stalks and seed heads are left alone wherever possible. On one hand, they offer food and cover to many animals: goldfinch, linnet and greenfinch will eat the seeds of Tragopogon pratensis and T. porrifolius, Dipsacus sylvestris, Carduus nutans and Arctium lappa. The hardened dry stems offer hibernation and pupation places to many insects. This way these animals can be attracted into gardens and parks. On the other hand, dead plants can be very ornamental, especially when covered with snow or frost. In spring, all of the decayed parts of the plants are cut off and cleared away. During the same work rounds, blown-in leaves and such are removed. If one does not do so, the formation of humus is encouraged, leading to rougher vegetations, and decreasing the aesthetic quality.
Woodland edge and fringe species constitute the harmonious transitions between open and closed spaces, between sunny spots and woods. These transitions of light and shadow offer spaces to many plant species, for example: Agrimonia procera, Aquilegia vulgaris, Digitalis purpurea, Vincetoxicum hirundinaria, Galium cruciata and G. sylvaticum, Geranium phaeum, Lathyrus sylvestris, Euphorbia amygdaloides, Campanula persicifolia, Geum rivale, Polygonatum multiflorum and several fern species. Some other species are best used singly or with a few grouped together, sometimes in narrow ribbons or small groups. They may be used to create special accents, provide depth or place a few ‘pearls’ in the open field. A few examples are Euphorbiapalustris, Asparagus officinalis, Parietaria officinalis, Cirsium oleraceum and Osmunda regalis.
