Prunus Spinosa Care: Tips For Growing A Blackthorn Tree

Blackthorn (Prunus spinosa) is a berry producing tree native to Great Britain and throughout most of Europe, from Scandinavia south and east to the Mediterranean, Siberia and Iran. With such an extensive habitat, there must be some innovative uses for blackthorn berries and other interesting tidbits of information about blackthorn plants. Let’s read on to find out.

Information about Blackthorn Plants

Blackthorns are small, deciduous trees also referred to as ‘sloe.’ They grow in scrubs, thickets and woodlands in the wild. In the landscape, hedges are the most common use for growing blackthorn trees.

A growing blackthorn tree is spiny and densely limbed. It has smooth, dark brown bark with straight side shoots that become thorned. The leaves are wrinkled, serrated ovals that are pointed at the tip and tapered at the base. They may live for up to 100 years.

Blackthorn

trees are hermaphrodites, having both male and female reproductive parts. The flowers appear before the tree leafs out in March and April and are then pollinated by insects. The results are blue-black fruit. Birds enjoy eating the fruit, but the question is, are blackthorn berries edible for human consumption?

Uses for Blackthorn Berry Trees

Blackthorn trees are extremely wildlife friendly. They provide food and nesting space for a variety of birds with protection from prey due to the spiny branches. They are also a great source of nectar and pollen for bees in the spring and provide food for caterpillars on their journey to becoming butterflies and moths.

As mentioned, the trees make a terrific impenetrable hedge with an enclosure of painful spike laden interwoven branches. Blackthorn wood is also traditionally used for making the Irish shillelaghs or walking sticks.

As to the berries, the birds eat them, but are blackthorn berries edible for humans? I wouldn’t recommend it. While a small amount of raw berry will probably have little effect, the berries do contain hydrogen cyanide, which in larger doses may definitely have toxic effect. However, the berries are processed commercially into sloe gin as well as in wine making and preserves.

Prunus spinosa Care

Very little is needed in the way of care for Prunus spinosa. It grows well in a variety of soil types from sun to partial sun exposures. It is, however, susceptible to several fungal diseases which can cause blossom wilt and, therefore, affect fruit production.

Sloe and easy

Blackthorn blossom
Blackthorn blossom

We are having an early spring – in London, where it is always warmer, things that would not normally flower until the end of April are in full bloom. It is most disconcerting.

Out here in the countryside (I live about seventy miles outside the city – which may not sound like much to you guys but remember that we are a very small island) things are still a bit out of kilter. One of the very first plants to flower in our hedgerows is the Blackthorn (Prunus spinosa) which is right now doing its thing with reckless abandon.

I am rather fond of Blackthorn even though it is a bit of an underdog in the grand scheme of things. It is not really good enough to be a stand alone garden tree but as a constituent part of a hedge is is invaluable. It has particularly unpleasant thorns which make it a pretty tough stock proof barrier against cattle and sheep.

The thorns have a nasty habit of going septic if they get into your skin: the only way to stop it is an operation to find and remove the offending bit of thorn. Does not have to be very big: if you want to cure yourself of ever going near a Blackthorn without, at the very least, some stout gauntlets and possibly a full suit of armour then read this.

The flowers are only small but, for the brief moment in which they stand alone and unchallenged by any other hedgerow plant, they are very cheering in a modest sort of way. A great cloud of white appears way before the leaves and is pollinated by insects – unlike the other early flowerer, the Hazel, which ids pollinated by wind. Or Anemophily if you want to show off.

Although it may not be much of a glamourpuss it is unbelievably hospitable to the larvae of a whole load of moths including the beautifully named Mottled Pug

In the Autumn the tree produces Sloes: these are small black berries which should be harvested just after the first frosts and are used for making Sloe Gin – which involves soaking the bletted* sloes in gin and sugar for many weeks. The raw berries are to be avoided as the are so astringent that they seem to suck all the moisture out of your mouth and leave you grimacing like a post operative MIckey Rourke

The wood is used to make the Irish Shillelagh (one of the most difficult words in the world to spell) which is a heavy club for bonking people over the head. It also makes walking sticks for the officers of the Royal Irish Regiment.

So… now you know pretty much all you need to know about Prunus spinosa. A shrub that is useful, beautiful, edible and a little bit dangerous.

Very similar to a girl I met in 1981….

*bletting is the process where berries soften when frozen – this accelerates the rotting process. In short, bletted fruit is damaged and beginning to rot. Yumm.

1 star
Plant: March to April
Harvest: November to January

The tough, hardy blackthorn bush is ideal for any difficult patch in your garden. The astringent, globular berries will do miraculous things to gin.

Recommended varieties: “No named varieties of sloe are available,” says Bob Flowerdew, “and most plants sold are seed grown.”

Sowing and planting: Sloes are the fruits of the blackthorn – a hardy bush that thrives on poor soil and is often found growing in Britain’s hedgerows (being the first common shrub to flower each year, it’s easy to identify). They make excellent windbreaks and don’t mind exposed sites. Healthy young trees can be grown from existing suckers or from shallow-planted seed. If you plan to grow young plants as hedges, they should be planted at a 45-degree angle, and staggered in two or three close rows, each laid in opposite directions. The shrub, which can grow to 4m, has blackish bark and disorganised branches and twiglets that end in a thorn.

Cultivation: Weed and mulch young bushes in spring to help them become established. Prune in summer if necessary and protect your fruit from the birds in autumn.

Pests and diseases: Though bluish-black, sloes are sadly still visible to birds. Protect with nets if they start to take more than their share.

Harvesting: Fruits are ready to harvest from late autumn. Wait until after the first frost though, or they will be very bitter. If you do pick before the first frost, try putting the berries in the freezer overnight.

Storage: Best stored inside a full bottle of gin! Prick each berry several times, add brown sugar and a couple of almonds and steep for several months before drinking.

Extending the season: You will only find fruit in winter, but happily the blackthorn has a white or pinkish blossom in early spring. Occasionally it will also flower prolifically during a cold snap (known in some parts as a blackthorn winter).

Growing in a container: This bush is best grown in the ground. Pick from the wild if you don’t have room in your garden.

Sloe (Blackthorn)

The sloe or blackthorn is a common plant native to the UK that has a wide range and it found from Siberia to the Mediterranean and Iran. It is a deciduous shrub that can grow up to 3m in height. It is often used as part of a hedge or as an understory in dappled shade or at the edges of a woodland garden. The fruit is used to make jellies jams and drinks like sloe gin. With visual interest and a yield, sloes are of interest to those who are interested in creating a layered permaculture garden. Parts of the shrubs have a whole range of other applications.

Growing Sloe/ Blackthorn:

Blackthorn grow well in dappled or partial shade or full sun. They can grow in light, medium or heavy soils though they prefer it to be moist but well-draining. Almost all soil pH levels, except acid peats, are fine, these plants can even grow in very alkaline soils and maritime conditions. It is very useful as a hedge in exposed maritime conditions, where other hedging plants may sometimes struggle.

Prunus spinosa is in flower with a white-pinkish blossom from March to April and the seeds ripen in October. Sometimes blackthorn will also occasionally flower during a cold-snap which is sometimes colloquially known as a ‘blackthorn winter’. Plants can be grown from seed or from suckers planted in the spring and new bushes should be weeded and mulched in spring to help them to establish themselves.

If you wish to create a wind-break or hedge from blackthorn you should plant the young shrubs at a 45 degree angle in two or three staggered rows laid in opposite directions. The shrub can grow to up to around 4m. It has very hard wood with blackish coloured bark and a tangle of branches and twigs that end in a thorn.

Birds love the sloe fruits so you may find that that begin to take more than their fair share. If birds are eating all of your sloes before you get a look in you may have to put up nets to stop them. If you would like to eat the astringent fruits, wait until after they have been exposed to a few frosts, which will make the taste a little less harsh.

Why grow sloe/ blackthorn in the garden?

The blackthorn is an extremely useful shrub. It is well known for attracting wildlife and pollinating insects and so is perfect for a wildlife garden or hedgerow.

The fruit is of use in condiments and, most famously, to flavour gin. In France the unripe berries are picked like an olive and in some places, fruit can be eaten raw once the frost has tempered its astringency. Both fruits and leaves are sometimes used for herbal teas.

The wood of the blackthorn is also very useful. It is a hard, strong wood which can be used to make many objects, including walking sticks. It is very highly prised for this purpose because the gnarled and twisted shapes made by the branches are highly decorative and interesting.

Prunus spinosa – Blackthorn or Sloe plant

A very interesting plant with two main uses, firstly Prunus spinosa is used as a hedge plant. It is a deciduous but dense shrub with thorny branches, make a great barrier. Secondly we have the berries which are used to make Sloe Gin, a bit of a traditional drink in the UK countryside.

Reaching around 3 – 5 m in height the Sloe or Blackthorn flowers in spring and the berries that form after the flowers are ready for picking in late summer to autumn. On first taste these berries are a little sour, however they are not only used to infuse gin and brandy, but also for making jellies, jams and the like.

The flowers in spring appear in masses covering the whole plant like a cloud of snow before the foliage appears. In Australia, Prunus spinosa is best grown in cooler climates as the fruit is a little sweeter if picked just after a cold spell or frost. One of the few plants that perfumes better (fruit wise) in frost prone climates)

Care

This is a tough hardy plant that requires little care. Perhaps best suited to a hedgerow at the side of a rural road, but also grown in the garden, particularly by those who use the berries.

Not particular about soil except the need for good drainage this is aslant that can be pruned back in winter to retain a more compact growth habit.

In dense shade the plant will not perform well, so some sunshine please.

Prunus spinosa is available for sale from the following growers

YAMINA COLLECTORS NURSERY – phone (03) 9756 6335
‘Justly famous for rare and unusual plants’ Don Teese
34 Mt Pleasant Rd Monbulk VIC 3793
www.yaminacollectorsnursery.com.auWHITE HOUSE NURSERY – Jess Exiner & Peter Harris
412 James Lane, Fern Hill VIC. 3458 – Phone 0419002651
Large range of Rare plants, Climbers, Bulbs, Perennials Fruit Trees, Ornamental Trees and Shrubs. Available both Retail and by Mail Order
www.whitehousenursery.com.au

Blackthorn Hedging

Distance apart:

Smaller Blackthorn plants should be planted at a distance of 30cm apart in a single row or sometimes people prefer to plant them in a double row with plants 50cm apart in each row, the distance between the two rows is usually 30-50cm. Larger plants won’t need to be planted as close, but how close will depend on how soon you want your hedge to look full.

Preparation before planting

The ground should be clean and free from weeds and grass. This gives the new plants a good chance to get established. If the area you are going to plant them in has grass or weeds, the ground should be sprayed off a week or so before planting to avoid any competition. To help prevent too many weeds appearing after you have planted your hedge, I find it a good idea to put your grass clippings or mulch around the plants as this smothers out the weeds and helps prevent the plants drying out.

Depth

The plants should be planted deep enough to cover the roots. They do not like to be planted too deep as this may kill them or stunt their growth.

Blackthorn doesn’t like to be lying in water so if the area you want to plant them in is wet, you may need to consider draining the ground or making a mound/ditch of top soil on top of the ground and plant them into this.

Blackthorn can grow well in full sun and partial shade.

Aftercare

Once the Blackthorn is established you can trim it once a year. Mid to late summer is a good time to give it a trim. It shouldn’t be trimmed if the weather is really hot and dry. You can give your hedge a feed of any high nitrogen feed (e.g. in the nursery we use 18-6-12) or poultry manure pellets in late spring/early summer. If the ground needs to be sprayed for weeds, winter is the best time to spray the ground as the plants are dormant.

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