Willows are found in a remarkable variety of sizes and shapes, and they grow nearly the world over.
However, the vast majority are known only to botanists while several species are immensely popular, with a couple even being iconic trees.
Willows are integral components of the British landscape, be it the forests or front gardens.
Overview
| Botanical Name | Salix |
| Common Name(s) | Willow |
| Plant Type | Tree |
| Native Area | Temperate Northern Hemisphere |
| Hardiness Rating | H5-H6 |
| Foliage | Deciduous |
| Flowers | Various |
| When To Sow | January, February, March, November, December |
| Flowering Months | March, April |
| When To Prune | February, March |
Members of this genus are commonly supposed to be native to the sub-arctic and temperate regions of the Northern Hemisphere.
In fact, Salix species are native to both hemispheres and all climatic zones from sub-arctic to tropical including equatorial.
Some or another species of Salix is native to nearly every country, and these include Willow Trees.
For example, Humboldt’s Willow is native to South America and Cape Willow is native to Southern Africa.
Most Willow Trees, though, are native to Europe, and also northern Asia and a belt of land spanning the United States and Canada.1
These deciduous trees are among the earliest ones to regenerate in spring, their pretty and colourful catkins that emerge in early April usually precede the leaves.
The leaves are almost always simple and alternate, and those of most species are lanceolate while some species have oval leaves.
Almost all Willows are dioecious meaning that a tree bears either male or female flowers, in the form of catkins.
Habitat & Growing Conditions
Other than Antarctica and Oceania, some or another species of Salix is found on every continent and nearly every region covering every climatic zone.2
Where Willow Trees proper are concerned, they predominantly inhabit temperate zones in the Northern Hemisphere, particularly in Europe.
Their preferred habitat is a full sun location in moist ground, including heavy, damp soils.
They are very frequently seen growing by or near water, from high banks of ponds and streams down to estuaries.
These trees are fully hardy in the United Kingdom, with the different species having hardiness ratings of H5 and H6.
Where To Plant Willows
Willow trees in the main should be planted in full sun and in consistently moist soil such as that by a brook or a pond.
Willow trees’ strong roots naturally seek out sources of water and they have been known to invade upon underground pipelines, sewage lines, and septic systems – so be sure to plant Willows at a healthy distance from such underground structures!
Where you should best plant a Willow Tree is entirely dependent on the species. Consider the Golden Weeping Willow and the Tortured Willow.
The traditional siting beside a stream or pond for a Weeping Willow is really the best one for it, and more so when it is accompanied by surrounding complementary greenery such as ferns and flower bushes – it is a pastoral landscape tree.
In distinct contrast, Tortured Willow is a rugged landscape tree, even an ‘accent tree’ with a ‘hard’ character.
It should be planted in an isolated location all by itself where its form will stand out.
Flamingo Willow can be planted quite close to your dwelling where its attractive seasonal colours can be viewed from the bedroom windows as well as from the dining room.
Blue-Stem Willow could just as well be treated as an accent shrub and planted by the walkway near the front door for your guests to admire.
How To Grow Willow
Many, though not all, Willows take root quite readily from cuttings.
In end-spring to early summer, take a softwood cutting of 40-50cm, and simply put it into moist soil of the type outlined above, be it in the open ground or a container.
Continue watering it, and when you see fresh shoots emerging you will know the cutting has taken root.
For the most part, though, Willow trees are planted as young potted specimens bought year-round or bare-root plants bought from winter to spring from specialist nurseries.
Both forms are easy enough to transplant:
- If planting a bare-root sapling, set it in a pail of water first and allow the roots to soak.
- The planting hole should be deeper and wider than the root system.
- Spread out the roots, backfill the hole, and push and pack in the soil between and over the roots.
- Give the new tree a generous watering, and ensure that it continues to get an ample supply of water.
Willow Care
The keys to growing thriving Willows are moist, even damp, soil and full sun exposure.
Soil Requirements
Willows flourish in fertile soils.
A mixed loam, which may be heavyish, amended with organic compost is perfect for Willows.
A soil pH in the Moderately Acidic to Neutral range – 5.6 to 7.3 – is ideal though these trees will do quite well in even Strongly Acidic soil.
If, besides full sun, the planting site is by any waterway or pond, then that’s twice as much joy for the tree and less maintenance for you.
“The need for moist soil should not be ignored when making the decision to plant a willow,” shares Master Horticulturist Dan Ori.
“With hosepipe bans and mains water bills rising, I have seen many willow trees fail in private and public gardens across the UK over the last few years.
“If you don’t have moist soil most of the year a good alternative may be a variety of Eucalyptus. Like willow, there is a diverse range of Eucalyptus species and varieties, so you are likely to find one that suits your needs.”
Feeding
Among trees, Willows number among the few that are happy feeders.
An annual ‘treat’ of an organic, balanced slow-release fertiliser right at the start of spring will be beneficial to the tree’s new bloom.
Common Problems
Very interestingly, Willows in the main are healthy trees that are not known to be unduly affected by pests and diseases but at the same time, the list of pests and diseases that can affect them is very long indeed.
The somewhat serious pests include aphids, gall mites, sawfly larvae, and willow scale.
Caterpillars and flea beetles are the less serious problems that may affect these trees.
Most any variety of Willow can be sickened by willow anthracnose, scab, and rust diseases.
In addition, a smaller number of varieties can also get willow heart rot, crown gall, honey fungus, root rot and tar spot.
The above ‘laundry list’, as it were, is not meant to alarm; it is provided only for the sake of completeness.
It should be noted that a particular variety will be more susceptible to one or another pest or disease whereas another variety will be more susceptible to some other pest and disease.
It would be wise to ask the seller exactly which pests and diseases you need to watch out for as to your particular variety of Willow Tree.
References
1. The Editors of Encyclopaedia Britannica. (2023i, March 12). Willow | Definition, Species, & Facts. Encyclopedia Britannica. Retrieved March 27, 2023, from https://www.britannica.com/plant/willow
2. Salix. (n.d.). Kew Royal Botanic Gardens. Retrieved March 27, 2023, from https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:325916-2
