Garden Trees for Wildlife
We’re being increasingly encouraged to plant garden trees for wildlife.
We plant trees for many reasons; to provide shelter, shade, fuel, food or even just to please the eye.
But trees are an essential part of our landscape and an integral part of our wildlife habitat!
Of course trees for wildlife can fulfill several of these other attributes and certainly need not be dull to look at.
Many of the best trees that are good for wildlife are among the most decorative of all trees. They are especially suited to smaller spaces too.
Whilst the oak is top of the list as far as number of species supported is concerned it is not a great choice for anything other than a very large garden!
So let’s take a look at some of those species that are good for our smaller gardens and especially good for wildlife.
In no other order than alphabetical I start with the alder.
Now alders are mostly native trees that tolerate wet soils.
But they will also grow on normal well drained soils.
However where the soil is heavy clay and lies wet in winter, this is a tree that will put up with those conditions.
Not the showiest ornamental tree but nevertheless it is one of the earliest to flower. It produces long yellow catkins opening soon after the hazel catkins in late winter.
Alder is very easy to establish and grows quickly to around 10 metres high.
It has a narrow crown and tolerates pruning well.
Top choice – Alnus glutinosa or a variety of it.
The ‘Snowy Mespilus’ or Amelanchier is a top seller and with every reason!
Here is a tree that ticks a lot of boxes! And when your garden is small you need plants that work hard for you!
In spring, just when every cherry is a blaze of blousy pinks and whites, the Amelanchier is covered in a snowstorm of tiny slightly pink tinted white single flowers.
The single blooms are good news for any hungry insect that is looking to get a quick fix of nectar.
The flowers are quickly followed by the emerging leaves.
By July and August tiny red berries appear but are not there for long since these are loved by birds.
As summer turns to autumn the leaves change to glorious shades of yellow, orange and golden browns.
The ultimate dense twiggy branch network can provide excellent shelter and nesting places for birds.
Top Choice – Amelanchier canadensis
Birch need little introduction and most are planted for their glistening white bark.
All are quite fast growing.
They do well on well drained soil and even tolerate thin shallow poor soils too.
They, along with rowans and alders, are a good choice for soils that have been trashed by builders. And so are a good choice for recently built houses.
Virtually all have a narrow growth habit that broadens with age – I know the feeling!
Topping out at around 15 metres high you would perhaps worry that this is too large. But the dainty canopy and small leaves provide delightful dappled shade and, equally important to some, very small leaves to pick up in autumn!
Although the long spring catkins are wind pollinated and so of little interest to insects, birds waste no time in ‘working’ the branches for other insects. These they take back to their fast growing fledglings.
Top choice – Betula utilis jacquemontii or Doorenbos
Cherries are a huge group!
Among them there are many excellent choices for both wildlife and for attractive garden trees.
I must say that I personally am not a great fan of the blousy Japanese double flowering cherry. But I know that it has its devotees.
I believe that these much hybridized varieties are also less popular with wildlife too!
For me the simplicity of single blooms wins hands down.
If you like those double flowered varieties then I’m sure that you won’t have to look far to enjoy them in a neighbour’s garden!
Cherries flower early and provide that early feast for insects that is so important after a long winter.
Black fly and caterpillars like cherries too and are snapped up by hungry tits of every kind.
Expect most to grow to 5 metres but with wide crowns of similar size.
Do beware that roots on these can come to the surface and make themselves a nuisance on tightly mown lawns.
Some cherries like my top choice produce stunning autumn colour.
My Top choice is Prunus sargentiana.
This is often thought of as just a ground cover plant.
Wrong! There are some good small trees in this genus too!
These are evergreen and provide cover for birds in winter.
Most also are prolific berry producers that larger birds – especially thrush family – relish.
At only 3 metres high [and often that wide too] this is at the smaller end of the tree range.
Trees often need staking for much of their life since they do not make extensive roots.
This might be a useful attribute if you want a tree near to buildings.
Top choice – Cotoneaster Cornubia.
Crab Apples, just like like cherries, offer many good choices!
However their susceptibility to diseases such as scab and canker narrows the choices somewhat.
Some provide plenty of showy fruit.
Others produce enough to make delicious crab apple jelly! But also enough fruit to share with the birds in winter.
Winter bird visitors from Scandinavia, [fieldfares and redwings] feast on these in their droves.
Trees provide good shelter and nesting sites for birds and at 5-10 metres high are not particularly large.
Some, such as Malus floribunda, make a great show of blossom in spring and it is those that we should be planting.
However, rather than going for this one that actually produces very little fruit I am inclined to recommend a better one.
This one has the distinct advantage to the gardener growing dessert and cooking apples that it is an excellent source of pollen. It will lead to better crops in your orchard!
Top choice – Malus Evereste
Hawthorns are prickly customers but that is often just what song birds need. When a sparrow hawk swoops into the garden they need shelter!
Hawthorns provide dense prickly shelter that only a foolhardy bird of prey would venture into.
But hawthorn, botanically known as Crataegus, are good for insects too!
Even the double flowered varieties like red Paul’s Scarlet and soft pink Rosea Flore Plena will attract bees and all manner of flies to their flowers.
Those with single blooms invariably produce masses of haw berries.
These persist long into winter and are a reliable source of winter food for wildlife.
Most hawthorn grow to just 3 metres but my choice is bigger at 5 metres and has great autumn leaf colour too.
Top choice – Crataegus prunifolia
Field Maple is not often planted in gardens but it does make an excellent dense hedge!
The flowers are hidden but the seeds are plentiful and eaten by rodents such as mice and squirrels.
This maple copes well with just about every type of soil.
It’s an excellent choice for windy places. And it’s an easy tree to grow.
In autumn the dense canopy is one of the last to lose its leaves.
Before it does those leaves change to a superb butter yellow!
Top choice – Acer campestre
Holly is of course an evergreen.
But holly is slow growing.
It grows best in shade and would be a good choice for city gardens where this is an issue because of large trees nearby. Or perhaps because of shade from buildings.
The very early flowers are pollinated by flies and, on female varieties, followed by showy berries.
Plant both male and female clones to be sure of berries.
Holly is useful to put behind the picture frames at Christmas and the berries are loved by the thrush family. The berries are quickly cleared by migrating redwings and fieldfares from Scandinavia.
Holly trees can get above their normal 3-4 metres when in shade but react well to regular pruning. Top choice – Ilex aquifolium ‘Alaska’
Rowan, also known as Mountain Ash, also grows to 3-4 metres.
Consequently they are perfect for today’s smaller gardens.
They will grow in poor soil conditions.
However just like all newly planted trees they grow better if the soil is well prepared and the trees are watered well until fully established.
The bunches of spring blossoms have a goat-like or almost rotting flesh smell to them.
Perhaps this is why they attract flies to pollinate them.
Don’t be put off by this since the fruits that follow are showy and often persist well into winter.
The common rowan [Sorbus aucuparia] is the first to ripen and fruits are gobbled up by birds quickly.
The white, yellow and pink berried varieties give a show for longer but those paler berried varieties need carefully siting in the garden. Try to choose a spot where there is a darker background so that the pale fruits are not lost against a grey winter sky!
Most varieties give excellent autumn leaf colour.
Top choice – Sorbus Joseph Rock
Trees to avoid
Trees to avoid because of large size are oak, beech, Eucalyptus, poplar, lime and plane.
However, beech is eminently suitable for a hedge.
It’s also wise to avoid elms, ash, horse chestnut and Robinia pseudoacacia ‘Frisia’ because of disease and pest issues.
When to plant garden trees for wildlife
November through to early March is the traditional planting time and still the best time in many ways.
Pot grown trees can, with good after care, be planted any day of the year.
Where to plant garden trees for wildlife
Any tree should be planted well away from buildings and as a general guide no closer than 6 metres is sensible.
Cotoneaster and holly could be planted much closer to buildings than other trees.
Avoid planting over the top of underground drains and equally planting under power lines is foolhardy.
How plant and after care
Most trees will need staking until the root system is well established.
Trees planted into established grass will struggle since grass provides surprising competition for water and nutrients.
It is a good idea to kill off any grass within at least a metre diameter of the tree.
Once established, the grass [or garden plants] can be allowed to grow back and this may help to keep more vigorous trees smaller. It might even entice them to produce more flowers and fruit.
Here I demonstrate how to plant a bare root tree. Do watch this short video.
Watering newly planted garden trees for wildlife
Generous watering throughout the spring and summer of the year following planting is a must.
And by generous I am not talking about splashing a bit of water on the soil from a hose pipe with your finger on the end! A new tree is likely to need at least 2-4 gallons [that’s two buckets full!] per week.
So with National Tree Planting Week right at the end of November this year what garden trees for wildlife will you be planting?
Are there better garden trees for wildlife that you would recommend?
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