A small garden is not easy to plant well. However, you could always decorate your patio, terrace or even a balcony with a miniature portable rock garden. A miniature Japanese garden, a rockery or even a water feature with water lilies would look superb, installed in a rectangular stone or clay container. Abroad, it is a common practise to plant miniature rock gardens in large troughs of tufa or hypertufa, which is a mixture of peat, cement and sand.
Tufa is a soft and porous stone, which absorbs water like a sponge. It takes no time to drill a hole in it and plant a houseleek or a saxifrage. Such a planting should be watered from above, in order to wet the whole rock, however, there is no need to do so often. If tufa stone is bedded into the soil by at least a few centimeters, then you can forget about watering, since the stone will absorb moisture from the ground when necessary.
Hypertufa is very similar to tufa stone in appearance, but it is neither warm, not soft. Large troughs made of hypertufa are very heavy and difficult to move. On a positive side, any home gardener can make a hypertufa container, they look quite ornamental and are inexpensive to produce. Hypertufa does not crack in response to cold. And if you want a weathered look for your hypertufa trough, all you have to do is to smear it with soured milk or yoghurt and leave it in a damp shade for the summer.
An interesting garden feature is a raised alpine bed. In fact, it is the best solution if you garden on a site, which tends to get waterlogged. First, make a timber frame to the height of 30 to 40 cm. Depending on the desired effect, arrange the pots within the bed. If you are happy with the way your rock garden looks, construct a stone wall around the frame, or alternatively remove the timber and build a low stone wall.
First, cover the bottom of the container with 3 to 5 cm of coarse drainage material: gravel, crushed stones or rubble, since most alpines hate growing in a waterlogged soil. If you are planting up a raised bed, increase this layer to 10 or 15 cm. The next job is to fill the container with fast-draining potting soil, made of 2 parts sand, 1 part peat and 1 part fertile loam. When using lime-loving plants, such as bell-flowers, it is best to plant them in small ‘pockets’ of appropriate soil or in pots, disguising them between the rocks or other plants. When preparing planting mix for these plants, use crushed eggshell or chalk instead of peat. Most perennials will need at least 20 to 30 cm layer of soil, while annuals will be happy with a mere 15 to 20 cm.
In a miniature rock garden, avoid mixing rock types. Choose just one kind, whether it is dolomite of greenish or yellowish shades, or basalt, or granite. Slate can be used to create an interesting effect. The rocks in your garden should look as natural as possible, so experiment with placing them until you achieve the look of a genuine landscape. The stones should be in scale with the size of the rockery, for example, 1 to 3 fist-sized stones would fit comfortably in a rockery measuring 50 x 60 cm.
Do not go to the extreme of planting alpines in pure sand on the assumption that most of the drought-tolerant plants cannot stand waterlogged soil and frequent watering. No plants will be able to survive such growing conditions, unless you enrich poor sandy soil with loam or compost.
Alpines refer to drought-tolerant and sun-loving compacts plants, many of which come from higher elevations. The majority of these plants are low-growing in a variety of forms (mat-forming, trailing and climbing), with strong yet compact roots, which help the plants to adapt to various conditions including exposure to heat and harsh wind, low moisture and poor soil. You can also plant dwarf, slow growing conifers, or compact deciduous trees, provided there is enough space for their roots to develop between the rocks. They can make a very attractive feature in such a setting, especially when grouped together according to their shape (round, columnar, cushion or mat).
There is an enormous choice of superb plants suitable for growing in rock gardens: moss phlox, snow-in-summer, various low-growing stonecrops, thymes, houseleeks, several saxifrages, alpine rock cress, mountain alyssums, alpine drabas, armerias, alpine campions, lewisias, decorative plantains, alpine asters, silver speedwells, mound-forming campanulas and dianthus, lamb’s ears, coreopsis, creeping baby-breath, perennial sage, ornamental trailing forms of oregano, several cultivars of cranebills, blue creeping sedge, pussy-toes, marguerite daisies, androsaces, to mentions but a few.
Spectacular houseleeks, saxifrages and stonecrops can be planted in various combinations to create colorful patterns. Hundreds of exciting and rare alpine plants are available from many nurseries abroad. Some of the exotics would weather the Lithuanian winter perfectly well, while others would have to be moved for overwintering inside the house or into a cellar.
Tender and frost-sensitive plants (escheverias, etc.) are usually planted into the alpine troughs in their pots, and should be moved inside once the autumn sets in, while evergreens should be moved to a frost-free spot. Keep in mind, that plants in raised containers are more susceptible to freeze damage. So, rather than leaving the hardy plants in the containers over the winter, you should consider planting them out into the garden. You could also dig a hole in the ground, and sink the whole container in it, covering it with fir twigs and peat, when the earth starts freezing over. Or you could move the container into the cellar, which should have a window if your planting includes at least one evergreen plant.
© Giedra Bartas, 2011