Collecting and propagating seeds
IntroductionFind out about ecosourcing, and how to collect and grow seeds.
What is ecosourcing?
Ecosourcing is collecting seeds close to where they are to be planted. It's an important part of a restoration project. It means the plants will be suited to local conditions and more likely to survive.
By using ecosourced native plants you will help maintain the area's unique local characteristics. Ecosourcing will avoid the risk of planting species which are not native to the local area and which could become invasive.
Growing from seed rather than cuttings ensures wider genetic diversity. Cuttings can be all exactly the same as the plant the cutting was taken from. The genetic diversity from seeds is especially important with longer-lived trees.
Don’t expect more than 50% of seed to be viable. Most native seeds are only viable in the ground for one or two years. (There are of course exceptions – miro can take up to two years or longer to germinate.)
Ecosourcing principles for a restoration project
Follow these principles when carrying out an ecological restoration project.
1. Plant species which are known to be native to the local area.
See the Local planting guides.
2. The closer the seed source to the restoration project the better.
Even in instances where species have become sparse and localised in their occurrence or have become locally extinct, the seed source for plants should be as close as possible to the restoration site.
3. Seed should be collected from a similar ecosystem to the one being restored.
Some species grow in a variety of ecosystems and are capable of surviving a wide range of environmental conditions (e.g. manuka will grow in both wet and dry ground). It is good practice to choose plants grown from seed collected from a habitat and set of environmental conditions which simliar to the restoration site.
4. Planning for restoration projects must allow for the timeframes involved in collection and propagation of ecosourced plant material.
This may mean a wait of two years or more between the inception of the programme and the plants being put in the ground.
5. Collection of seeds or propagules should take place from areas of native vegetation which are clearly of natural origin.
Collection from roadsides or small stands of native trees which are in a park setting or are surrounded by developed land is unsatisfactory as there is a good chance that the stock has been planted from non-local sources.
Ecosourcing plants from nurseries
If sourcing from a nusery, find one that grows ecosourced native plants (not every nursery does) and check the following.
- The plants are grown from seed collected from wild plants for restoration purposes.
- The is a record of where the seeds were collected. Check that it is close to your planting site. A plant may be ecosourced but the seed might not be.
Choose the best practical source of plants for your project.
Where to collect seeds
Before collecting seeds, check with the landowner. You need a permit from DOC to collect from conservation land.
The best place to collect seed is along forest margins where more flowers and seed are produced. Also collect along roadsides, tracks and stream edges. Avoid collecting from areas that have been planted, or where there is likely to be cross-pollination from nearby garden plants.
The way seed is dispersed has an impact on the distribution and natural variability.
- Species that are wind-pollinated (eg podocarps, beech and grasses) have the least geographic difference.
- Species that are bird or insect pollinated (or dispersed) are variable across different climates, landforms and soils. They should be collected as close to the planting site as possible.
- Seeds of threatened species should only be collected from the same population to where you want to plant – unless you want to secure and increase genetic diversity from nearby populations that once were contiguous (you'll need DOC approval).
When to collect seeds
The main collection period is late summer and autumn. Seed is ready to collect when it is ripe. This varies from plant to plant, but seed will either fall or change colour.
The time it takes for seed to ripen depends on the plant, locality and the year. Seed ripeness can vary by one or two months from year to year. You may need to check plants several times over the period when seed fall is expected.
How to collect seeds
Collect a little seed off a lot of plants of the same species. This ensures a broader range of genetic material. Never collect all the seed – some should be left for natural regeneration.
Collect only undamaged seed – watch out for insects or rodent damage. You can collect more than once in a season so you have a range of both early and late fruiting specimens.
- Collect carefully – try not to damage the plant.
- Remove ripe seeds individually or cut off clusters or small branchlets.
- Collect seed off the ground during seed fall.
- You may be able to tether shadecloth near the ground and collect seeds that fall into it. This can be used for any large tree with seed that falls straight to the ground, eg kauri, totara, kahikatea, rimu and tawa.
- You may need long-reach pruners to reach the seed.
Collection and propagation guides
Find when and how to collect seeds and propagate some common native plants and trees.