[bonsaisever]

Tamamı : http://www.rhs.org.uk/learning/publi...506/maples.asp
Çeviri yapıldı

Growing dissectums
Contrary to popular belief, Japanese maples do not need acidic soils to grow well. They will succeed on most garden soils except the extremely alkaline, waterlogged or really dry. These are forest understorey plants, adapted to semi-shade, shallow but humus-rich soils, the shelter of a higher tree canopy and relatively constant moisture levels. Their biggest enemies are winter waterlogging (their fine, fibrous root systems are prone to rots) and late spring frosts. Japanese maples leaf out relatively early in the season and while frost damage to emerging leaves is rarely fatal, it can knock them back severely. Slow-growing dissectums can take time to recover from frost damage, although their small stature does at least make fleecing an entire plant during spring cold snaps possible.

If you garden on chalky, free-draining or heavy clay soils, Japanese maples in general, and dissectums in particular, adapt well to containers, and plants in pots can be brought under cover when frost threatens. A loam-based, John Innes-type compost with up to 20 percent added grit or perlite to improve drainage is ideal. Never allow the compost to dry out entirely; scorched leaves, their edges brown, dry and papery, will result. Pot-on gradually, every two or three years.

Scorch can occur with plants grown in the ground, too. Strong sunlight or winds can strip moisture from the leaves faster than the roots can replace it, and given the amount of edge to the leaves of dissectums they are particularly vulnerable. As with frost damage, scorch looks unsightly but plants usually recover and affected leaves can be cut off.

Most purple-leaved dissectums colour best in good light, but given the potential for scorch, this does not mean full sun, which is risky for all cultivars. Variegated cultivars are most prone to scorch in sun, so shade is crucial. Like all Japanese maples, dissectums have shallow root systems, so an organic surface mulch both conserves moisture and feeds the plant (more on Japanese maple cultivation). Be sparing of feritiliser - too much tends to produce lots of soft growth that is vulnerable to sun, wind, drought and early autumn frosts.

None of this should suggest dissectums are difficult to grow, however, for they are not - give them moisture at the right time and site them correctly in sheltered locations with some shade and they will repay handsomely with cascades of peaceful foliage that often changes colour with the seasons.

Placing dissectum maples
Dissectums should not be given vigorous neighbours, whether herbaceous or woody. Their delicate appearance suggests equally fine- or small-leaved companions. Selections with different leaf colours contrast effectively with each other, and they also look beautiful placed in front of more vigorous, upright Japanese maples such as Acer palmatum ‘Osakazuki’, A. palmatum ‘Sango-kaku’ (coral-bark maple) or exquisite A. shirasawanum ‘Aureum’ (golden full moon maple). Keep them far enough in front of the rootball of the larger plant, however, to avoid competition. Dissectums also mix well with other favourites of the Japanese garden such as evergreen azaleas, camellias and pieris, and even feathery grasses such as Stipa tennuissima or Deschampsia cespitosa.

On a smaller scale, including pot groupings, team dissectums with other foliage plants using complementary or contrasting colours and shapes. Red and purple dissectums go well with blue hostas, Ophiopogon planiscapus (black-leaved ‘Nigrescens’ or plain green), or the strappy, arching leaves of broad-leaved sedges such as Carex siderosticha or C. glauca, and plain or variegated Luzula (woodrush). The finely-divided leaves of smaller ferns such as Athyrium niponicum var. pictum (painted lady fern), Cyrtomium falcatum (Japanese holly fern) or cultivars of Polystichum setiferum Plumosum or Divisilobum Groups echo the dissectum leaf beautifully. Mounded green dissectums could be matched in shape with refined grass Hakonechloa macra ‘Aureola’ or the intense blue cushions of Festuca glauca ‘Elija Blue’, or contrasted with the bold, blood-red uprights of Imperata cylindrica ‘Rubra’ (blood grass) or the green, black-banded stems of Equisetum hyemale (scouring rush).

It is not just in Japanese or foliage gardens that dissectums can shine, however: their low mounds of foliage are equally at home in modern spaces, or potted on a contemporary deck. Green-leaved selections can blend demurely into the background, while purples and reds used as specimen plants demand attention. All are irresistibly tactile. Dark blue or reddish glazed pots complement rusty red and purple cultivars well, and a pair of potted dissectums would frame a doorway beautifully.

All colours look wonderful in splendid isolation close to water, and fare well at the edges of streams or ponds (if the soil is free-draining enough), where their foliage can luxuriate in the high humidity.

The less-vigorous dissectum cultivars are small and slow growing enough to be used in large rock gardens, as they are at RHS Garden Wisley. The delicate tracery of their bare, twiggy outline makes an excellent foil for early spring bulbs such as snowdrops, Chionodoxa, Leucojum and dwarf daffodils, while their mounded form makes an elegant backdrop to cushion-forming alpines such as saxifrages and sedums.

Pruning
Although dissectum maples do not need pruning, they form such a congested dome that the curved or downright serpentine beauty of their trunk and branches is hidden. Selective pruning to open up this internal structure to sight not only makes them look better aesthetically, it allows light and air into the canopy, reducing potential problems with fungal diseases and pests lurking inside. Dissectums are best pruned in summer.
In Japan, dissectums are often grown in pots raised well off the ground to bring their fine structure closer to eye level, and are prized as much for the filigree beauty of their winter branches as for their foliage.
Fern-leaf or dissectum variety Japanese maples are among the most beautiful of all foliage plants. They may not flower conspicuously but certainly mark the changes of season: the shy emergence of their vividly-coloured spring leaves declares the true end of winter, subtly shifting into a more demure but luxuriant midsummer dress of lush, feathery, cascading foliage before taking on dazzling autumnal robes. Even when the last leaves have fallen, the elegant scaffolding that is revealed continues to have impact.

These are plants that command attention in all seasons, with a presence far larger than their diminutive size suggests.