librarian2003 (librarian2003) wrote in weagardening, @ 2011-01-24 18:31:00 |
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Week 1 - Plant of the Week : Small Trees
Our Plant of the Week for this term will be Small Trees. This includes some large shrubs that can be trained into the shape of a small tree.
Members have bravely agreed to take a tree or shrub each, and do some research then tell the rest of us what they have found. Well done, everyone.
Here is the handout:
GARDENING FOR PLEASURE
Plant of the Week : Small Trees
There are many trees widely available for smaller gardens, in all shapes and sizes, evergreen and deciduous. Given that many of us have limited space in which to garden, it becomes most important that any trees chosen are right for their surroundings, in terms of proportion as well as for their decorative value. There are many factors to take into consideration when choosing a tree for a small garden. Here are some of the more important ones:
•Height and spread: This is probably the most important factor. Even small ornamental trees may, over time, reach a height of 6-7m (18-21ft) or more. If this is too much, consider a weeping form, as these rarely increase much in height. Spread is not normally such a problem, unless in a very restricted area, in this case consider a columnar tree, as these do not spread appreciably. This with a thin canopy will cast less shade than those with a dense canopy.
•Season of interest: Consider when you want your tree to look good, thinking about flowering time, foliage, fruit and bark. If you only have room for one tree ideally look for one with more than one season of interest such as fruit or autumn colour following on from flowers.
•Deciduous or evergreen: Both types of trees have their advantages, the obvious one for evergreens being that they keep their leaves. But you don’t get the lovely autumn colours with evergreen trees.
However, creative pruning can turn a shrub into a tree, and a large shrub can make an excellent small tree. Most of us consider that a tree is a tree by virtue of its central woody trunk; similarly, we regard a multi-stemmed woody plant as a shrub. Yet, we've all seen stands of multi-stemmed white birches as well as large, single-stemmed cotoneaster. Virtually any shrub that doesn't sucker excessively from its base is a good choice for pruning into a tree; one that does sucker or flowers on new wood (roses, for example) may not be suitable. A shrub trained into a tree is less aggressive than a small tree (a term often used to just mean “slower growing”), and its augmented height is especially useful as a vertical accent in a perennial border of any size.
Training a shrub into a tree does require some patience. Buy small, one-year-old specimens, if you have the patience. A more mature plant is better trained into two or three trunks to form a multi-stemmed tree; just treat each stem you select as though you were training a single-stemmed specimen.
STEP-BY-STEP GUIDE
1 Select a healthy, vigorous plant with an obvious upright central stem, which will become the leader, or main trunk, of your tree. Then plant the shrub as you would any other.
2 Remove all branches on the bottom third of the shrub. Leave the top two-thirds intact for the rest of the year: the extra foliage is essential for providing food and energy as the plant becomes established.
3 Insert a stake as close to the central leader as possible and attach using soft string, fabric or a commercial tree tie.
4 Repeat step No. 2 (limbing-up the shrub to one-third of its total height) each spring until the desired height is reached, usually between 75 and 150 centimetres. This process can take anywhere from three to five years if you begin with a one-year-old specimen.
5 Once the desired height of the trunk has been reached, it's time to develop the tree's canopy. The following spring, select three or five of the largest branches at the top of the plant. They should be evenly spaced to ensure an open framework, enabling light and air to penetrate. Clip these stems back by seven to 12 centimetres to encourage lateral growth. Remove all other branches in the canopy and along the trunk, and discard the support stake.
6 To maintain your tree-form shrub, prune off any branches that sprout along the trunk, and thin out the canopy as necessary.
Small trees or large, trainable shrubs for consideration in Plant of the Week.
Apple Malus
Crab apple Malus
Birch Betula
Cherry Prunus
Juneberry Amelanchier
Rowan Sorbus
Weeping pear Pyrus
Hawthorn Crataegus
Mount Etna Broom Genista aetnensis
Pineapple Broom Cytisis battandieri
Judas Tree Cercis
Cotoneaster salicifolius ‘Rothschildianus’
Cotoneaster hybridus pendulus
Cotoneaster cornubia
Cotoneaster x Watereri
Contorted hazel Corylus
Cornus kousa
Wisteria
Buddleia
Lilac Syringa
Laburnum
Species and Cultivars to consider:
Flowering Trees
•Crataegus laevigata ‘Paul’s Scarlet’ AGM – dark red flowers in May and June. Height 24ft.
•Genista aetnensis AGM – yellow flowers in July. Height 24ft.
•Magnolia loebneri ‘Leonard Messel’ AGM – lilac-pink flowers in April and May. Height 24ft.
•Malus baccata ‘Lady Northcliffe’ – pinkish-white flowers in May, with yellow/brown crab apple in autumn. Height 18ft.
With particularly attractive fruits:
•Malus ‘Evereste’ AGM – white flowers in late April followed by yellow fruits. Height 21ft.
•Prunus ‘Accolade’ AGM – soft pink flowers, which are 1½in across, in May. Height 24ft.
•Prunus ‘Pink Perfection’ AGM – double pale pink flowers 2in across in March and April. Height 24ft.
Flowering trees with autumn colour
Small for neutral to acid soil:
•Cornus kousa – white bracts in June. Height 21ft.
•Cornus kousa var. chinensis AGM – white bracts in June, but taller than the one mentioned above. Height: 23ft.
Small for any soil pH:
•Prunus ‘Shirofugen’ AGM – double pale pink flowers 5cm across in April or May. Height 24ft.
•Prunus ‘Shôgetsu’ AGM – double white flowers 5cm across in April or May. Height 15ft.
•Prunus x subhirtella ‘Autumnalis Rosea’ AGM – blush pink flowers 2cm across from November to March. Height 24ft.
Medium for any soil pH
•Cercis siliquastrum AGM – rose-purple flowers in April to May. Height: 30ft.
•Koelreuteria paniculata AGM – yellow flowers in July and August. Height 30ft.
•Malus floribunda AGM – red in bud, opening pink then white, and red/yellow fruits. Height 10m 30ft.
Trees with coloured foliage in spring and summer
Small:
•Acer negundo ‘Auratum’ – golden yellow leaves, turning paler in summer. Height 24ft.
•Acer pseudoplatanus ‘Brilliantissimum’ AGM – pink leaves in spring that turn yellow by summer. Height 18ft.
•Pyrus salicifolia ‘Pendula’ AGM – silver grey leaves and a weeping habit. Height 15ft.
Medium:
•Sorbus aria ‘Lutescens’ AGM – silver-grey foliage, and yellow autumn colour and fruits. Height 10m 30ft.
Trees with autumn colour for neutral to acid soils
Small:
•Acer japonicum ‘Aconitifolium’ AGM – deeply-lobed leaves, turning ruby-crimson in autumn. Height 5m 15ft.
•Crataegus persimilis ‘Prunifolia’ AGM – crimson fruits and good foliage colour. Height 24ft.
•Sorbus vilmorinii AGM – rose-red to white fruits and good foliage colour. Height 5m 15ft.
Medium:
•Amelanchier lamarckii AGM – white flowers in April. Height 10m 30ft.
•Styrax japonicus AGM – white flowers in June. Height 10m 30ft.
•Acer griseum AGM (paperbark maple) – peeling bark; red and scarlet foliage in autumn. Height: 10m 30ft.
Medium trees with autumn colour for any soil pH
•Malus zumi ‘Golden Hornet’ AGM – yellow fruits, 2.5cm (1in) across. Height 10m 30ft.
•Prunus ‘Pandora’ AGM – shell pink flowers 3cm (1.2in) across in March or April. The young leaves are bronze-red, colouring richly in autumn. Height 10m 30ft.
•Malus moerlandsii ‘Profusion’ – pink flowers in April; red/orange fruits in autumn. Height 10m 30ft.
Autumn colour and fruits
Small:
•Acer palmatum ‘Atropurpureum’ – bronzy-crimson leaves. Height 8m 24ft.
Medium:
•Sorbus commixta ‘Embley’ AGM – orange-red fruits and good foliage colour. Height 10m 30ft.
•Sorbus sargentiana AGM – scarlet fruits and good foliage colour. Height 10m 30ft.
•Prunus cerasifera ‘Nigra’ AGM – dark purple leaves. Height 10m 30ft.
Coloured stems and bark plus autumn colour
Small for neutral to acid soil:
•Acer palmatum ‘Sango-kaku’ AGM – coral-red young branches. Height 6m 18ft.
Medium for neutral to acid soils:
•Acer capillipes AGM – bright red young growth, and branches streaked green and white. Height 10m 30ft.
Coloured stems and bark
Small:
•Eucalyptus pauciflora subsp. niphophila AGM – mottled green, grey, cream bark. Height 18ft.
•Acer griseum AGM – dark, flaking bark to reveal orange underneath. Height 18ft.
Evergreen
Small:
•Arbutus unedo AGM – flowers white in spring and fruits red in October and November. Height 24ft.
•Cotoneaster salicifolius ‘Rothschildianus’ AGM – a semi-evergreen with yellow berries. Height 15ft.
•Eucalyptus pauciflora subsp. niphophila AGM – grey-green leaves and a patchwork-bark. Height 18ft.
Medium:
•Ligustrum lucidum AGM – white flowers in August and September. Height 30ft.
Tall and Narrow (fastigiate or columnar)
Small:
•Prunus ‘Amanogawa’ AGM – columnar, with erect branches. Pink blossom in spring. Height 24ft.
•Sorbus aucuparia ‘Fastigiata’ – a slow growing, columnar small tree with closely erect stems. Height 24ft.
Medium:
•Prunus ‘Spire’ AGM – a vase-shaped tree with orange/red autumn foliage. Height 30ft.
Weeping
•Malus ‘Royal Beauty’ AGM – reddish-purple flowers and dark red fruits. Height 6½ft.
•Prunus ‘Kiku-shidare-zakura’ AGM – pink flowers in April. Height 3m 10ft.
•Ulmus glabra ‘Camperdownii’ – a neat, compact tree with small green leaves. Height 8m 24ft.
Sources:
http://apps.rhs.org.uk/advicesearch/Pro
http://www.canadiangardening.com/ho
Other information:
http://www.trees-online.co.uk/index.p
http://www.guardian.co.uk/lifeandst
Jo Hanslip
January 2011
Here's the pro-forma to help you with your research:
GARDENING FOR PLEASURE
Trees/shrubs for the small garden
Name
Tree or Shrub
Evergreen or Deciduous
Size
Season(s) of interest
Main attractions
Any difficulties
Soil requirements
Cultivation requirements
Pruning requirements
Suggested position
Worthwhile cultivars and hybrids
Pests and diseases
Hardiness
Other points
And here is the schedule:
Tuesday Group
1 Maureen - Amelanchier
2 Jean - Pineapple Broom and Mount Etna Broom
3 Jean - Hawthorn
4 Joan - Crab Apple
5 Sheila - Rowan
6 Judy - Cotoneaster
7 Hugh - Cercis
Friday Group
1 Tracy - Contorted Hazel
2 Jean - Rowan
3 Margaret - Cornus
4 Mary - Cotoneaster
5 Helen - Amelanchier
6 John - Crab Apple
7 Enid - Apple
8 Shirley - Pineapple Broom and Mount Etna Broom
9 Paul - Hawthorn
10 Carole - Wisteria
And here are some pictures to get you going:
Small Trees
If you have any images for your slot, let me know and I will post them.
Jo