Q What does planting bulbs 'in the green' mean?
A We're often told that for the best chance of success, small spring-flowering bulbs (and tubers), such as winter aconites, bluebells and snowdrops, should be planted while they have leaves in early spring ('in the green') rather than as dormant bulbs in the autumn.
The argument given for this is that small bulbs can easily dry out while in storage, so are better lifted while in growth then replanted straight away.
Which? Gardening magazine wanted to know if this was really the case so we trialled planting in the green compared to autumn planting for snowdrops, winter aconites and bluebells.
Caption: Planting 'in the green' means planting while the bulb is in growth
Q Should snowdrops (galanthus) be planted in the green?
A Which? Gardening magazine found no significant difference between planting in the green in spring or planting as dormant bulbs in autumn in the number of bulbs that came back in the second year.
However, the results were more variable between different suppliers, indicating that the bulbs' chances of establishing were actually more dependent on the quality of the bulbs supplied than at what time of the year they were planted.
The most successful group of snowdrops were bought in the green and had an establishment rate of around 76%. But one group of bulbs, also bought in the green, had an establishment rate of just 12%.
Caption: The quality of the bulb is more important than time of year for snowdrops
Q Should bluebells be planted in the green?
A We had a very high success rate planting both in the green in spring and as dormant bulbs in autumn, with all the bulbs thriving and increasing in the second year. However, when they came into flower it was clear that two of the groups of dormant bulbs we had been sent were actually
a hybrid of Spanish and English bluebells, rather than the English bluebells we thought we were getting. As these are much more vigorous than English bluebells, we were unable to compare them.
With the rest, however, we found that the dormant bulbs and bulbs in the green established equally well.
Q Should winter aconites (Eranthis hyemalis) be planted in the green?
A These relatives of the buttercup add some much needed colour to the garden in early spring.
Unfortunately they proved very tricky to grow, with a shockingly low number of flowers appearing in the second year of our trial.
We did discover that it was better to plant them while they were in the green in spring, but even then we still only got around 50% of the plants reappearing the following spring.
The dormant bulbs we planted were very hit-and-miss, with establishment rates varying between 30% and 0%.
Caption: Winter aconites (Eranthis hyemalis) are more successful when planted in the green