Before leaving the subject of group planting sphagnum moss should be mentioned as a possible plunging material. Moss of this kind has many advantages, not least the fact that it is light, clean and easy to handle, and that difficult plants seem to do particularly well when plunged in it. Recalling my personal. experience with the success of a difficult plant may help to emphasise the advantages of this material.

By keeping the peat moist it will be found that the plants do not require to he watered as often as those placed individually on the window ledge. However, having emphasised the need for keeping the peat moist one must add a word of warning against overdoing it, as plants cannot possibly be expected to do well in the soggy mess that will result from too frequent watering.

Grouped together plants create a certain amount of humidity and feeling around one another, and this is a very important requirement in hot and dry room conditions. In the greenhouse we can combat the dry atmosphere created by the heating pipes by frequent damping of the area around the plants, and by wetting the ground beneath the staging and the pathways as frequently as possible.

Purely by chance we discovered the best way to grow this plant when a container, measuring some 3 ft. across, was filled with sphagnum moss into which plants of D. Pia were plunged to their pot rims before being taken to a minor show. Containers filled in this way with one sort of plant can often be much more effective than a collection of assorted plants in the same sized container. Anyway, the large howl of plants came back from the show and, instead of adopting the usual practice of dismantling the arrangement, we left it intact and placed it in a warm greenhouse.

When adopting this method it is important to choose plants for grouping together which are reasonably compatible in their moisture requirements, as they will all have to suffer or enjoy the same conditions. For example, the moisture-loving cyperus would not be expected to do particularly well in the same container as a sanscvicria which prefers very much dryer root conditions.

Keeping the gravel permanently moist will ensure that there is a certain amount of essential humidity around the plants, but it is important that, though the gravel is wet, the plant pots must at no time actually be standing in water as this will inevitably result in waterlogged soil conditions.