If there is a very damp position in the garden it may be used as the site of a bog garden for the cultivation of those plants which grow in moist or swampy ground in their native habitats. If no such site is present, construct for draining away the water to prevent its becoming stagnant. The site should be forked over, all weeds eradicated and liberal quantities of leaf mold or compost dug in the soil. If the bog garden is of considerable extent, stepping stones are required to give convenient access to the plants and to facilitate their management and inspection.
How to Make a Bog Garden. In gardens where swampy spots suitable for the cultivation of bog plants do not exist, it may be desirable to construct an artificial bog garden. The area is marked and the soil dug out to a depth of about 30 in. The basin so formed is then puddled with a thick layer of clay or is lined with concrete. When dry, it is filled with garden soil to which leaf mold or peat moss has been added freely.
The Water Supply. An overflow pipe is fixed level with the surface on one side to carry away surplus water. The entrance to this must be covered with a piece of perforated zinc, to prevent its becoming blocked by debris. Water is supplied to the garden by a small pipe from the main or from a large storage tank, or a hose pipe may be used in dry weather.
The plants should be arranged in irregular groups, the low-growing kinds in groups of at least half a dozen, and the larger kinds in twos or threes.
The Most Suitable Plants. A great variety of attractive plants are available for furnishing the bog garden. Among the dwarfer kinds are the Bog Pimpernel, Anagallis tenella, 3 in.; Astilbe simplicifolia and its varieties, and A. chinensis pumila, 1 ft.; double Marsh Marigold, Caltha palustris monstrosa-plena, 10 in.; Cuckooflower, Cardamine pratensis flore pleno, 9 in.; the Clintonias, 1 ft.; Trilliums, 9 in.; the Lesser Celan-dine, Ranunculus Ficaria, 4 in.; the Swamp Pink, Helonias bullata, 18 in.; Pitcher Plants, Sarracenia, 1-2 ft.; Forget-me-nots, Myosotis, 6 in.; Bog Bean, Menyanthes, 9 in.; Rhexia virginica, 9-12 in.; Dodecatheon, 12-18 in.; Hosta or Funkia, 2 ft.; graceful Willow Gentian (Gentiana ascelpiadea); the pygmy Gunnera chilensis (scabra) minor, 14 in.; hardy Lady’s Slipper Orchid, Cypripedium Reginae (spectabile); C. Calceolus pubescens and some other wet soil orchids, including species of Habenaria and Orchdis; yellow Skunk Cabbage, Lysichitum americanum, with its enormous leaves; various Musks, Mimulus; Grass of Parnassus, Parnassia palustris, 6 in.; the handsome May Apple, Podophyllum, 18 in.; pink Saxifraga peltata; and the numerous moisture-loving Primulas such as P. Beesiana, P. Bulleyana, P. denticulata, P. Florindae, P. helodoxa, P. japonica, P. pulverulenta and its hybrid strains, and P. sikkimensis.
Of taller-growing moisture-loving plants suitable for the bog garden if space permits, special mention may be made of the Japanese Irises (Iris Kaempferi) in many varieties, and the Yellow Flag, Iris Pseudacorus; Astilbes, Aruncus, and herbaceous Spiraeas; the Giant Reed, Arundo Donax; the giant-leaved Gunnera manicata; scarlet Lobelia cardinalis, and light-blue L. siphilitica; graceful white Lysimachia clethroides; Loosestrife or Lythrum; the Zebra Grass, Miscanthus (Eulalia) sinensis zebrinus; the Ostrich Fern, Pteretis nodulosa; and the beautiful Royal Fern, Osmunda regalis.