A cheap and eco-friendly way to grow trees
SEASON Now is a good time to collect seeds - Teagasc expert
When deciding to plant a tree at home the vast majority of people head to their local garden centre to buy one. But why should that be?
There's a cheaper, much more rewarding, and arguably more ecologically sound way to go about it - collect seed and grow your own tree. So why do more people not do it?
"I just don't get it," admits Steven Meyen of Teagasc, "because it truly is really simple. Over a couple of months you'll see fantastic results - a little tree starting to grow."
After some thought, Steven surmises: "I think it's because we're so far removed from nature, and we're especially far removed from trees and what they can do for us in our daily lives, that people have lost that connection.
"Maybe it's a bit like - milk doesn't come from a cow, it comes from a carton in a shop. If you want a tree, you go to a garden centre and buy a tree."
To show just how simple the process is for many native Irish trees, Steven has drafted two concise worksheets, available on the Teagasc website.
Some trees, particularly those which produce berries, involve a few more steps, but they are by no means insurmountable.
Steven likens it to following a recipe. Some recipes are trickier than others, but if you follow the steps and modify to your own preferences, you’ll see great results.
Collecting tree seeds
The Belgian native, who now lives in Donegal, says that seed collecting and sowing is a fun family activity, giving kids an excuse to get their hands mucky. And later they can marvel , 'that's Séamus's tree, and that's Mary's tree'.
For the vast majority of popular Irish species, October is a great month in which to collect seeds, nuts and berries. They may be gathered from the tree or the ground but ensure the tree is healthy. Avoid breaking off branches and always ask the owner’s permission.
Steven also advises against collecting the initial seeds that fall from a tree, known as 'the first drop'. That is when the tree dumps sterile seeds.
Giving the example of collecting acorns, Steven says: “Once they get rid of the sterile acorns, and you get maybe a good proper frost - that's when the real proper supply of acorns is going to come.”
The next step is a ‘flow test’ which couldn’t be easier.
“That’s a very fancy way of saying that you fill a bucket with water, you throw your acorns in and if anything floats or looks a bit nibbled, damaged or funny, you get rid of it. The ones that sink to the bottom, those are the ones that are more than likely fertile.”
The simplest trees to grow from seeds are any which produce nuts: oak, beech, horse chestnut, sweet chestnut, hazel.
After the ‘flow test’ you have the seeds for sowing.
“You get your milk carton [or small pot/container], punch a couple of holes in the bottom. You fill it with compost - leave a couple of centimetres at the top obviously. Take one acorn, put it sideways on the compost and with your thumb, shove it down into the compost, probably about the depth of your nail. Cover that over with compost, and keep an eye on it that birds, or mice or squirrels, or whatever, are not going run off with it.
“Job’s done - that’s it!”
Another “really easy one” Steven recommends is wych elm. The only drawback is that, somewhat unusually for Irish tree seed, you have to collect it in May.
“You will find heaps and heaps of winged seed on the wych elm - you collect that and sow it on a bed of compost, because it's really light, small seed. Cover it lightly with another little thin layer of compost - make sure that you keep it moist, and you'll be surprised how quickly those wych elms will start growing - even in the same year. After a year you have proper little elm trees, it's really fantastic.”
Steven accepts that wych elm are susceptible to Dutch Elm disease.
“Is that a good enough reason not to have them around the place? No I don't think so.
“Sometimes you do come across elm trees that appear to be resistant to the disease, and therefore wouldn't it be great if you were breeding a little elm tree off those trees?”
Not berry hard
Trees which produce berries, while still easy, involve a few extra steps in the tree recipe. These trees include the blackthorn, whitethorn, and the stunning spindle tree.
“It's produces beautiful berries – lovely orangey red berries,” he says admiringly of the spindle. “In Flemish, my language, we say it looks like the hat of a cardinal – and it really does.”
The first extra step required for dealing with berries is ‘maceration’.
“Maceration is basically a fancy word for getting the flesh off the seed,” explains Steven. “There are chemicals within the flesh and skin that will create a very deep dormancy for the seed.”
In nature if a bird were to eat berries, the flesh and skin would be removed when passing through its digestive system. To achieve the same result, put “a heap of berries” in a bucket, add a little water, and take a square bit of timber and gently mash them.
“Do it very carefully, very gently, then you gradually add more water and you'll find that the flesh and the skin will start floating to the top.”
Sterile seeds will also float to the top - which you pour off together with the pulp and skin.
“Eventually you end up in your bucket with a lovely heap of little off-white coloured round seeds.”
The next step is stratification, which means to mimic winter conditions. You can do this by putting a mix of one part seeds, one part building sand, and one part compost in a large plastic container with drainage. Cover it with a layer of sand and leave it outside over winter.
An alternative is to use a controlled temperature treatment. Keep the same seed, compost, sand mix in a sealed plastic bag. Leave in the fridge for four to 20 weeks depending on the tree species. Turn the bag periodically. In both the outdoor and the fridge system, sow seeds as soon as they start to germinate.
Steven explains that you are aiming to sow on March 1, so start with that date and work back for your timings.
If you want a challenge, the Guelder rose is in Steven’s estimation probably the trickiest.
“It can’t make up its mind whether it wants to grow or not,” laments Steven of the tree often found in hedgerows.
"It's really a stunner in the autumn and it's also really beautiful in the spring with the big white flowers.”
For this one you have to pick its attractive red berries in August when they are still ripening and put them in a plastic bag until the flesh and skins starts to rot.
Steven warns: “It stinks like hell.”
Wash the seeds clean in a bucket, and then sow immediately, covering them with about 2cm of soil or compost. The tricky part is in getting them to germinate, says Steven.
“Aw they are very frustrating - it's going to be a very mixed bag – some will germinate, others will not. It's funny.”
Even at that, he still estimates 50% would probably germinate – not bad for a collection of free seeds.
“It’s worth it,” he says.