Gathering seed to grow your own trees rather than purchasing them in a garden centre is a cheap, fun, and satisfying way of growing trees. One benefit of growing trees in this way is that you can source seed from a local stock of trees which have proved themselves to be adapted to your local area for things such as soil conditions and climate.
Tree seeds can be separated into four groups; nuts, winged seeds, fruit and cones:
Nut producers: this includes hazel (hazelnuts), oak (acorns)
Fruit producers: Rowan (berries), hawthorn (haws), holly, yew, wild and bird cherry, crab apple.
Winged seed producers: Wych Elm, birch, ash.
Cones: Scots pine.
When gathering seed, it is best to use cloth or paper bags (or envelopes) to store the seeds, as this prevents moisture buildup which can cause mould and kill the seeds. It is best to store them outside, in a dry, dark location so they are not exposed to indoor heat. With nuts, viable seeds can be fairly reliably separated from unviable seeds by pouring them into water; discard any seeds that float.
Where possible, it is best to mimic the method by which seeds naturally germinate.
Nuts: plant the nut an inch or two below the surface of the soil; nuts often germinate naturally after having been buried by squirrels for their winter store!
Fruit: remove the fleshy part of the fruit - this is often eaten by birds, and the seed passes through the bird unharmed.
Winged seed: these can be planted as is; they naturally fall to the ground to germinate.
Cones: these can be dried in a paper bag away from direct heat, which opens the cones and releases the seed. The seeds can be planted in a similar way to winged seed.
It is best to place the seedling, once germinated, into its final location as soon as possible, so the roots are not constricted by the pot. Also, small seedlings will not need staking. However, it may be necessary to mulch the soil to prevent grasses and weeds outcompeting the seedling, and it may also need protection from grazing animals such as deer if they occur in the area.
Acorns are easily found on Oak trees; these are best collected when they have fallen out of their cups and are a good size, and are easy to grow. Plant them an inch or two deep in the soil. The acorns pictured are on a Sessile Oak.
|Acorns are easily found on Oak trees; these are best collected when they have fallen out of their cups and are a good size, and are easy to grow. Plant them an inch or two deep in the soil. The acorns pictured are on a Sessile Oak.|
|Alder produce very small seeds, and only a fraction of these will be viable. It is best to collect the seed as soon as the capsules start to turn brown, but before they open. These can then be dried in a paper bag, which will cause the capsules to open and release their seeds. The seeds will germinate best if exposed to a period of cold weather to break their dormancy. They can be sown onto soil and only lightly brushed in, due to their small size.|
|Ash produces deeply dormant seed, which can take over a year of stratification to break their dormancy, going through a full winter and summer cycle. They will also benefit from several days soaking in water soon after collection to help break down the seed coat, but the water should be changed daily.|
|Birch seeds can be collected in autumn when the strobiles - the seed capsules - turn brown and dry, and can be easily broken apart with some mild pressure between your fingers. Given the size of the seeds, it's best to scatter these on the soil and only lightly brush them into the soil. The chances of germination are improved it they are exposed to a period of cold weather to break their dormancy. The scattering method is likely to produce lots of seedlings.|
|The bird cherry is one of the ancestor's of today's cultiavted sweet cherries, and as a result is edible, if not quite as appealing as sweet cherries.|
|Hawthorn berries; remove the flesh and test for viability by placing in water - seeds which float are probably not viable and can be discarded. They can be sown outside after collection, as they need the cold and wet of the winter to break their dormancy and will germinate in the spring.|
|Hazel is very easy to grow from seed (providing you don't fall to temptation and eat them before you can get them sown!) The nuts can be collected in late Autumn, and planted an inch or two deep in the soil. Hazel is wind pollinated, so it is best to have several within reasonable distance from each other to ensure pollination and a crop, if you wish to be able to collect hazelnuts from the plants you have grown once they begin to mature.|
|Holly is another seed which requires a long period of stratification, typically germinating in the second spring after they are produced; as such, it is a long term investment to grown them from seed. They can be sown outdoors, but in a position where they can be left to their own devices for 18 months.|
|Rowan seeds can be treated in a similar fashion to haws.|
|Due to the ongoing debate about whether there are any Scots Pine left in Ireland which are native, any seed you may be able to collect will almost certainly be from stock imported into Ireland with the last several hundred years.|
|The strawberry tree has a very limited range within Ireland, favouring the mild wet climate of the southwest. Its stronghold is in Killarney, so please be mindful that collecting seeds from this tree within National Parks there is restricted given its rarity.|
|Wych elm - these can be treated in a similar manner to birch.|
|Yew berries are easily distinguished; but beware that the red flesh on the berries is the only part of the yew which is not highly poisonous; all other parts (including the hard seed in the berry) are poisonous. They can be treated in a similar way to haws.|