ACER Most maples thrive on lime and chalk, including British natives and those commonly planted. The Chinese species, such as AA, capillipes, davidii, ginnala, griseum and rufinerve, make a splendid display in chalk gardens. A. palmatum and its cultivars need more fertile soil. The American A. rubrum will not grow on chalk.
AILANTHUS Tolerates lime.
ALNUS All alders will grow well on lime but must have moisture, with the exception of A. cordata and A. incana, which will stand drier situations. The former is good on chalk.
AESCULUS The horse-chestnuts and buckeyes do well on lime and chalk, though preferring fertile soils.
AM ELAN C HIER Though naturally growing on light acid soils, these will tolerate some lime.
ARBUTUS One of the few Ericaceae that grows well on lime.
BETULA The birches do well on lime. BUXUS Good on lime, the common box grows naturally on chalk.
CARPINUS All the hornbeams are successful on either heavy alkaline soils or light chalk.
CARYA Will tolerate some lime in deep fertile soils.
CASTANEA. The sweet chestnuts do not like lime, but will tolerate it in small quantities on well-drained fertile soils.
CATALPA Lime tolerant.
CELTIS Will tolerate some lime in deep, fertile soils.
CERCIDIPHYLLUM Lime tolerant. CERCIS The Judas trees do well on lime and chalk.
CORYLUS Hazels do well on lime, including chalk.
COTONEASTER. Most kinds do well on lime, including chalk.
CRATAEGUS All thorns will grow on lime and chalk.
DAVIDIA The dove tree does well on lime and chalk.
EUCALYPTUS There is still some doubt as to which species will grow well on lime.
EUONYMUS The tree-like species thrive on lime and chalk.
EVODIA Does well in shallow chalk soil.
FAGUS The beeches have a shallow root system and thrive on well-drained soils with high lime content and on chalk. FICUS The fig-tree grows well on lime and chalk.
FRAXINUS The ashes thrive on soils with high lime content as long as they are fertile.
GLEDITSCHIA Will tolerate a little lime in fertile soils.
GYMNOCLADUS The Kentucky coffee needs a rich, loamy soil and will tolerate some lime.
HALESIA The snowdrop trees will not tolerate lime.
IDESIA This rare tree is good on chalk. ILEX Hollies are good on lime and chalk. JUGLANS Walnuts will thrive on lime soils and chalk if it is not too thin. KOELREUTERIA The golden rain tree will grow in any well-drained soil. LABURNUM Will grow anywhere. LIQUIDAMBAR Dislikes more than a trace of lime and will not grow on chalk. LIRIODENDRON The tulip trees will grow on fertile soils with high lime content but are not happy on chalk. MAGNOLIA Magnolias are not happy on limy soils, the exceptions among the tree-sized species being MM. delavayi, x highdownensis, kobus, sinensis and wilsonii.
MALUS In varying degrees the ornamental species and hybrids of apples are satisfactory on lime, and the majority do well on chalk.
NOTHOFAGUS The southern beeches so far in cultivation in Britain will, on fertile soils, stand a little lime in the soil but cannot be grown on chalk. NYSSA A lime hater.
OSTRYA The hop-hornbeams will grow on lime.
OXYDENDRUM A lime hater.
PARROTIA Is not successful where there is more than a trace of lime. PAULOWNIA Good on lime and chalk. PHELLODENDRON Good on lime and chalk.
PLATANUS The planes do well on lime. POPULUS Poplars in general need fertile moist soil and will not object if there is a lime content, but, except for PP. alba, canescens and lasiocarpa, they will not grow on chalk.
PRUNUS Almonds, apricots, bird cherries, cherries (including the Japanese cultivars), laurels (common cherry and Portugal) and peaches, all grow on soils with a lime content and, in varying degrees, are also successful on chalk. PTEROCARYA The wing-nuts will stand lime if the soil is fertile and moist. PYRUS The pears will all grow on soil with a high lime content, including chalk.
QUERCUS Most oaks do well on soils with a high lime content, including chalk, if there is sufficient depth for their tap-roots. Particularly good are QQ. canariensis, cerris, frainetto, hispanica `Lucombeana’, ilex, macranthera, robur and petraea. Willow oaks, Q. phellos, and cork oaks, Q. suber, are not good on lime.
RHUS The tree-like species will grow on lime, including chalk.
ROBINIA The false acacias will grow on lime soils and chalk, but are not at their best on them.
SALIX The tree-sized willows tolerate lime, but all need abundant moisture, and will not thrive on dry, chalk soils. SAMBUCUS The common elder will reach tree size on lime and chalk. SASSAFRAS Requires lime-free soil. SOPHORA Tolerates lime on well-drained fertile soils.
SORBUS The rowans and service trees are all good on lime, including chalk. STYRAX The snowball trees will not grow on lime.
TETRACENTRON This rare Chinese tree does well on lime and chalk.
TILIA The commonly cultivated lime trees grow naturally on limestone formations, but need moderately fertile soils.
ULMUS All elms will grow well on lime and in varying degrees on chalk. UMBELLULARIA The Californian laurel will tolerate some lime but will not thrive on shallow chalk.
ZELKOVA The ironwoods will tolerate lime but must have deep fertile soils.
ABIES Most silver firs need deep, moist soil and in such will tolerate lime. AA. amabilis, bracteata, forrestii, grandis, magnifica, procera and Veitchii are not good on soils with much lime. AA. cephalonica and pinsapo, however, will grow on chalk.
ARAUCARIA The monkey puzzle given fertile soil will tolerate lime.
CEDRUS All the cedars, especially C. atlantica, will tolerate lime on fertile soils.
CEPHALOTAXUS These small trees grow well on lime.
CHAMAECYPARIS CC. lawsoniana and nootkatensis and their cultivars do well on soils with high lime content. CC. obtusa, pisifera and thyoides are not good on lime and will not thrive on shallow chalk.
CRYPTOMERIA The Japanese cedar will tolerate lime if grown in deep, moist soil.
CUNNINGHAMIA The Chinese fir is not happy on lime soils.
x CUPRESSOCYPARIS The Leyland cypress grows well on lime and chalk.. CUPRESSUS The hardy cypresses will tolerate lime, and C. macrocarpa does well on chalk.
GINKGO The maidenhair tree grows well on fertile soils containing lime. JUNIPERUS The numerous species and their cultivars grow well on lime. LARIX Larches grow well on lime. LIBOCEDRUS The incense cedar needs deep moist loam and will tolerate some lime.
METASEQUOIA The dawn redwood does best on fertile soils, with or without some lime, and will grow slowly and healthily on chalk.
PICEA The spruces are not happy on shallow, dry soils, though most will
tolerate some lime, including the much cultivated common spruce, P. abies. An exception is the striking Serbian spruce, P. omorika, which grows on limestone rocks.
PINUS Though many of the pines grow naturally on light, mountain soils and
many will tolerate a little lime, the
majority dislike it. Even the Scots pine, P. sylvestris, is not at its best on lime.
PP. armandii , contorta, pinaster, radiata,
and strobus are unsatisfactory on lime. The handsome stone pine, P. pinea, will
stand a little. The Austrian pine, P.
nigra austriaca is good on chalk, as to a slightly lesser extent is the Corsican
pine, P. nigra maritima. P. mugo, often no more than a spreading shrub, will also grow on chalk, as will the rare P. bungeana.
PSEUDOTSUGA The Douglas firs thrive on fertile, moist, well-drained soils, on which they will stand some lime but not chalk.
SCIADOPTYIS The umbrella pine will not grow on chalk.
SEQUOIA The giant redwood will tolerate lime if there is a good depth of fertile soil but will not grow on chalk. SEQUOIADENDRON The wellingtonia also will grow well in deep fertile soils but will not grow on chalk.
TAXODIUM The swamp cypress will not tolerate lime.
TAXUS The yews grow naturally on limestone formations and chalk, and are equally on good acid soils.
THUJA The western red cedar will grow on soils containing lime, as will the Chinese and American arbor-vitae and their cultivars.
THUJOPSIS This needs fertile, moist soils and thrives better on neutral or acid sites than on limestone.
TORREYA These yew-like trees do well on limestone and chalk.
TSUGA The western hemlock will not thrive on shallow soils containing lime or on chalk, nor will the other species occasionally planted. The eastern hemlock, T. canadensis, will, however, grow under these conditions.
Permanently wet soils The other soil factor that must be taken into consideration is continuous moisture, that is, soils that are continuously saturated. The majority of trees will not grow in these conditions, but those that will include the numerous kinds of willow (Salix), large and small, as well as the alders (Alnus), which are mostly trees of moderate size. The handsome and uncommon swamp cypress, Taxodium distichum, is also good, though very wet conditions are not necessary for its success.
Planting A tree will normally outlive its planter. However, if it is given a good start the planter will be rewarded all the earlier by vigorous growth. Do not attempt to plant a tree in unsuitable soil. The choice having been made, you should assure yourself that you are buying stock of good quality.
Broad-leaved trees (deciduous or evergreen) These may be purchased as standards, in which the clear stem is from about 2-2.3m (6-7ft). The smaller size is more satisfactory as a rule, and will soon catch up a larger one, which may well have an undesirably spindly stem.
In some instances, when, as in a Japanese cherry, low branching will look attractive, a half-standard can be used branching at from 1-1.5m.
Have ready a sound, pointed stake long enough when driven firmly into the ground to reach to the point on the stem where the branching starts, also one of the several types of tree ties now available.
Dig or fork around where the tree is to be planted for about an area of a meter (yard) square. Particularly if the ground is poor or heavy, work in some well-rotted compost or peat.
Remove the wrappings of the roots and cut off any that are broken. Dig a hole which will take the root system, as nearly as possible so that when the tree is stood in it, the soil mark on the stem is level with, or just below, the surrounding soil. It is, except where willows are concerned, very bad practice to plant too’deeply. When you have ensured that the planting hole has been dug to the correct depth, lift the tree out and drive the stake well in at about the centre of the hole.
Replace the tree, working the roots round the stake so that the stake is as close as possible to the stem. This is easily done if someone else holds the tree in place. If you are working single-handed, loosely tie the tree to the stake.
Work soil carefully among the roots, the fine soil among the fine roots, firming it carefully with the fingers. Then almost fill the hole, frequently firming it by gentle treading. Next water the tree well; when the water has sunk in, lightly fill the hole up. Finally, attach the tie at the top of the stem.
Conifers Conifers supplied are usually of a much shorter length than broad-leaved trees and seldom need staking. It is most important to disturb the root ball as little as possible. The sacking which binds the ball may be left on until the tree is in the hole. The knot or lacing that holds it is then cut and gently teased loose and left in the hole. If the tree is not absolutely firm, a stout garden cane and strong string should be sufficient to secure it.
Planting of deciduous trees should be done as soon after leaf fall as possible, but may continue until early spring before the buds begin to break.
Conifers are best planted in autumn, when they will make root at once, and be established by spring. It is less desirable to plant in winter when the roots are for long quite inactive. Early spring is the next best time, for root growth will soon be active. But watering during a spring drought with an east wind is then essential. A mulch is also helpful.
Maintenance and pruning The area round the base of the tree should be kept weeded until it is well established. Watch the tie regularly and keep it from becoming too tight, ie, allow a little play. Strangulation may cause great damage. Remove the stake only when the tree is absolutely firm—this will take at least three years.
To keep the tree shapely, preferably with a single leading shoot, the following rules should always be followed in pruning trees young or old.
Always cut a shoot or branch back to the point where it arises, making the cut as clean and flush and as close to the main branch as possible. If a ‘snag’ is left, it will not grow and will eventually rot and cause damage.
If the shoot or branch is of any weight, carry out the operation in two stages, the first taking off the weight and leaving a short snag that can then be removed without its bark tearing away back into the main stem. If the scar is large, paint it with one of the proprietary sealing paints.
Ornamental trees are in general best pruned from mid-to-late summer. The wounds then heal quickly and attacks by fungi or bacteria are held at bay. This applies particularly to most species of Prunus, especially cherries, It also applies to maples, birches and walnuts which ‘bleed’ sap during the winter and spring.
Never attempt to carry out pruning on a large tree; always obtain the services of a qualified tree surgeon. Unless properly done, it will probably result in damage and disfigurement of the tree, and in addition is often a highly dangerous undertaking for the unskilled operator.
Pests and diseases Those affecting ornamental trees can be divided into three main classes : disease due to bacterial or fungal action, damage caused by insects and damage caused by animals (including birds). Of the first, the most seriously affected trees are members of the rose family (Rosaceae).
Bacterial canker attacks cherries and plums. It is associated with the oozing and dripping of gum from branches or the trunks. Some control can be obtained by pruning out branches affected.
Silver-leaf also affects plums, cherries and apples in particular and occasionally thorns and laurels. The leaves take on a silvery appearance and on a branch that dies a purplish-mauve fungus arises. This should be cut out and burned without delay.
Fire blight may attack pears, hawthorns, rowans, whitebeams and pyracanthus. Whole shoots in leaf go brown, as if burned, and die. If this is found, the Ministry of Agriculture, Fisheries and Food must be notified at once. The most serious ‘killer’ fungus is the honey-fungus. It occurs generally on ground that has been woodland which has been cleared with the stumps or many large roots left in the ground. Root-like growths, resembling boot-laces spread through the soil and infect a healthy tree, which is eventually killed and should be removed. From the ground around it, toadstools may, but do not always, arise. They are pale yellow, the gills on the underside running a little way down the stalk, which carries a