Drought Tolerant Trees - Planting for the future
I want to plant a tree I can live with. But…
There are hundreds of trees to choose from. When judging the place of trees in Kentish villages for the Kent Men of The Trees (KMOTT), I often hear the question – which trees might survive a drier, hotter climate? I wanted to expand on my own favourites with more variety. So, I have trawled through and compared many references to create a longer list based on degrees of 'drought' tolerance. "Drought" also describes built-up areas that have hard-surfaces (pavements, decking, paved drives, roads) close to the planting site because water runs off and doesn't get readily absorbed into the soil. I have also tried to avoid trees known for their risk to nearby structures through vigorous roots near the surface.
Statistically, Kent has always been the driest part of the British Isles. Climate change has led to more frequent and extended periods without rainfall - not ignoring the more severe storms and damaging run off as well as inundation in low-lying areas.
| Planting trees: should take place between October and April, when they are dormant. The hole you dig should be square to help roots break away from the shape of a pot and spread! Include watering tubes in the ground (for watering and feeding deeper roots) and mix some Mycorrhizal fungi with the soil with which you fill the hole. |
| Finding your tree: If you search for the tree name on the RHS website - most result pages include the link - "sold by xyz nurseries". Alternatively - search the web! |
Go Native?
Should we stick with 'native'? Native trees do have the advantage that the rest of Nature knows what to do with them (their leaves, bark, flowers, pollen, roots, fruit, dead branches and trunks). But not all native trees are suited to "drought" conditions. So, bringing in "exotics" (non-native) may still provide nectar, pollen, seeds, fruit, and shelter. So, I have 'parked' a purist approach. If Nature is unable to keep up with the rate of climate change we may simply be faced with losses of species and nothing with which to replace them? Arguably, introducing more diverse habitats may be essential to a sustainable future? Well, it's a thought.
Now the practical stuff … "one tree or many?" … "small or open spaces".
Let's start with smaller trees. After all, we do still want to be able to enjoy and use our personal spaces. Today, there many choices of attractive large pots - use good quality tree/shrub compost, add a watering tube that you will also use for occasional feeding. Make sure of decent drainage (pebbles and/or broken pots at the bottom of the pot and try not to let the tree dry out completely! It is astonishing how little water drains through from just top-watering! Equally, waterlogging these trees should be avoided! Hedging is another story – perhaps visit the Millennium hedge in Cambridge Lane for inspiration!
"Jacks of All Trades" – Smaller and slow-growing trees that are drought and soil tolerant
Common Name(s) |
Latin |
Likely Tree Size in UK |
Varieties (Size in UK if different from a standard tree) |
Eastern Redbud |
Cercis Canadensis |
Small; <10m x 6m |
Hearts of Gold; Forest Pansy (purple leaf); Ruby Falls (weeping) |
Chitalpa, Summer Bells Tree |
x Chitalpa tashkentensis |
Small; (<10m) |
|
Cornelian Cherry |
Cornus mas |
Small; (3-8m x2.5-4m) |
Golden Glory. (Small; 2.5-4m x 2.5-4m) |
Cockspur Hawthorn, Thorn |
Crataegus crus-galli |
|
Prunifolia |
Woodland or Midland Hawthorn, May |
Crataegus laevigata |
Small; (4-8m globular) |
Paul's Scarlet, Punciea/ Crimson Cloud; Rosa/ Rosea Flore Pleno (2.5 x 4m), Gireoudii (2.5 x 4m) |
Honey Locust |
Gleditsia triancanthos |
Medium/ Large; (12-20m - 4-8m) |
f. inermis "Sunburst" [thornless, big but not dense cover] |
European Holly |
Ilex aquifolium |
Medium; (<12m - 4-8m; ovoid) |
Argentea Marginata (f), Handsworth New Silver, Pyramidalis, Silver Queen, Amber J.C Van Tol, Ferox argentea (m). |
Crab Apple |
Malus sylvestris |
Small/ Medium; (8-12m, bushy) |
Slow growing [20-50 years to maturity] |
Medlar |
Mespilus germanica |
Small; (4-8m, irregular, bee friendly) |
Large Russian Dutch (f) and Nottingham (f) |
Olive |
Olea europaea |
Small; (4.5-9m x 1.5-2.5m, irregular |
[foliage interest; in warm sites can fruit] |
Plums |
Prunus domestica |
Small; (All 2.5-4m x 5m - globular) |
Greengage: Cambridge Gage, Imperial Gage, Reine-Claude d'Oulins |
Sargent's Cherry |
Prunus sargentii |
Small; (<10m, globular) |
Rancho. |
Callery Pear |
Pyrus calleryana |
Medium; (12-17m) |
Chanticleer, Redspire. Order on a "QC" (dwarfing) Rootstock if space is an issue. |
Staghorn Sumac |
Rhus typhina |
Small; (4-8m x 4-8m; vase shaped) |
[Suckers freely; choose a site carefully!] |
Whitebeam |
Sorbus aria |
Medium; (10-15m) |
Lutescens, Majestica |
Common Lilac |
Syringa vulgaris |
Small; (<6m x 4m) |
Andenken an Ludwig Spath Vestale, Firmament, Primrose. |
CONIFERS |
|||
Common Juniper |
Juniperus communis |
Small; (<10m, conical) |
|
Rocky Mountain Juniper |
Juniperus scopulorum |
Small; (4-8m x <4m) |
Blue arrow (Steely blue foliage). Small; (1.5-2.5m x 0.1-0.5m, upright habit) |
Eastern Red Cedar |
Juniperus virginiana |
Small; (4-8m) |
|
Common Yew |
Taxus baccata |
Large; (12-18m x >8m, irregular) |
[Very slow growing species; tolerates very hard pruning] |
Irish Yew |
Taxus baccata |
|
Fastigiata (f), fastigiata aurea. |
Fussy Eaters – small and drought tolerant, but can be a bit picky about soil types.
Common Name(s) |
Latin |
Likely Tree Size |
Varieties to pick - limitations |
Pink Siris/Silk Tree |
Albizia julibrissin |
|
f. rosea - Small; (4-8m x 2.5-4m, bushy), avoid heavy soil |
Judas Tree |
Cercis siliquastrum |
|
Bodnant - avoid heavy soil |
Fig |
Ficus carica |
|
Brown Turkey, Ice Crystal - avoid heavy soil; best to restrict roots in the ground or plant in a large pot. Will need feeding. |
Domestic Apples |
– avoid shallow soil over chalk (most local gardens need not worry) & needs watering for fruit-forming but can fit any space – even in a large pot (which clears the chalk problem!) or alongside a path - see my later note on dwarfing rootstocks for fruit trees. |
||
Hybrid Mountain Ash |
Sorbus |
|
"Joseph Rock" |
Salt Cedar |
Tamarix ramisissima (T. pentandra) |
|
Rubra |
Four Stamen Tamarix |
Tamarix tetrandra |
Small; (2.5-4m x 2.5-4m, bushy) |
- avoid chalk |
Fruit trees on manageable rootstocks – this is a huge topic, but here is a place to start…
If you have a loamy, moist/damp but free-draining spot in your garden (brick earth for example) you have the option of 'dwarfing' rootstocks for several fruit trees to contain their size to manageable dimensions! You can also use large pots, but the trees will need a bit more care. Royal Horticultural Society (RHS) award-winning apples are listed above.
If 'dwarfing' is new to you … inhibiting tree-size is achieved through taking a cutting from a parent tree and 'grafting' it onto a rootstock specifically developed to restrict the growth of the cutting. All you have to do is choose the variety and ultimate size of fruit tree you want! That requires planning, patience and working with a (specialist) nursery. Once you know the final size (and shape, e.g. espalier) and variety of apple or other fruit tree that you want, you place an order and return a year or two later to take delivery and plant your new sapling.
Keeping it local: Brogdale is worth a visit or call (in Covid times) - they offer a service to graft your choice of fruit onto dwarfing rootstocks. The guide price I have from them (£35) would get you a graft onto a dwarfing rootstock ordered in January would be delivered in October! Online searches will show other specialist nurseries that may have exactly what you want already.
Picking Fruit Rootstocks:
- Apples (Malus Domesticus). For example, a M27 rootstock gives you an apple tree that grows to 5-6 feet only!
- Pear tree grown on a "QC" rootstock grows to 6-8 feet – by the way "QC" can also be used for Quinces.
- Cherries are a bit more difficult to dwarf – "G5" gives you a tree of 10 feet (3 metres).
- Plums are also quite tricky but a "Pixy" rootstock grows a tree of 10-12 feet height.
Upscaling
The opportunities for planting trees are as varied as the size and shape of our living spaces. Of course, in your garden, you can make very particular choices (colour, shape, scent, leaf, bark, etc) but, if you have access to more open spaces and land margins, your choices expand to include my full list! Mine is not a definitive list, but I have tried to avoid as many problem-trees as possible. I remain open to suggestions and alternatives of course!
Out and about or looking for more ideas for different conditions?
My personal book of choice for inspiration is the "Collins Tree Guide" – some books are just too big to carry! Of course, a second-hand Observer Book of Trees is a very good place to start. There are also many leaf-charts and tree profiles designed as educational aids. Or navigate online to websites such as the Royal Horticultural Society (RHS) or Tree Council.
Finally, an app … Plantnet. This may help you identify trees and other plants by using your smartphone's camera. It is free and a bit of fun but can appear a bit random.
Nigel Heriz-Smith.