Require Light for Germination

Recommended for the following species:
​
Butterfly Bush (buddleja davidii)​
​Indian Bean Tree (catalpa bignonioides)
Empress Tree/Princess Tree (paulownia tomentosa)
London Plane (platanus x acerifolia)
American Sycamore (platanus occidentalis)

​​All of these seeds must have light and very high levels of humidity to enable germination to take place.

​For sowing first fill a wide pot or seed tray with a good quality compost. Lightly but firmly flatten and consolidate the surface. Water the compost so that it is evenly moist all over. Take a pinch of seeds and lightly sprinkle the seeds over the compost surface. Take into account that the rates of germination are usually very high so do not sow the seeds thickly but try to keep the seeds spread out a little from each other.

To ensure germination high humidity must be provided this can be achieved by pacing a sheet of glass or clear plastic over the container. I have had good success using 5 short, thin metal hoops to support transparent pallet wrapping film (or cling film) above the compost surface and sealed around the edges, although a clear plastic bag would work equally well.

​The sown seeds then need to be placed in a place that receives plenty of light but not direct sunlight. If sufficient light is not available additional artificial light should be used. After a day or so the water vapor will begin to condense on the inside of the film indicating 100% humidity inside and the correct conditions for the surface sown seed to germinate.

After approximately a week or so kept at room temperature signs of germination should be evident. After another week or so covered by the film the edges need to start to be lifted slightly to increase air circulation and start to prepare the seedlings for life under more normal atmospheric conditions

In good conditions the seedlings develop rapidly. They will very soon need to be individually transplanted into larger containers. It is preferable to produce shorter, stocky, well branched seedlings rather than long leggy ones. These can only be grown if the plant density is relatively low.

Keep the seedlings well watered and free from competing weeds and protect seedling from early autumn frosts. Growth is rapid and trees should be planted in their permanent positions before growth starts in the second year.