If you want early flowers this spring you must get your bulbs in soon because they require the chilling that comes with winter.
Yes, unfortunately it’s hard to manipulate bulbs to flower when you want, according to Paul Hoek at NZ Bulbs, and this is especially the case with spring-flowering varieties.
“In a nutshell, spring flowering bulbs can’t just be planted later to make them flower later.”
Paul says exactly when they flower will depend on how cold the winter is, how much rain there is, and how early or late spring comes.
“It’s also hugely dependent on where you are in NZ.
“The only way to make spring bulbs flower later than normal is to plant them in pots and hold them in a chiller, progressively lowering the temperature from nine degrees Celsius to zero degrees Celsius during a period of 10 weeks.
“Then hold them at zero and take them from the chiller two to three weeks before you want them in full flower. This approach won’t work with unplanted bulbs.”
To make potted spring bulbs flower earlier, you can use the chilling method above and simply take them out early rather than late.
“But there’s only a small window in which you can make them flower earlier. Tulips can’t be chilled until late-March because the immature buds inside the bulbs need to reach a certain development stage before they’re ready.
“And, they need to be chilled for a minimum of 12 weeks. So approximately August would be the earliest you could get tulips to flower – about three to four weeks ahead of normal,” says Paul.
For potted daffodils and hyacinths you can start chilling earlier, in early March, and have flowers in early July.
You can also get unplanted bulbs to flower earlier. But instead of putting them in at nine degrees Celsius, you can put them straight in at four degrees Celsius. Do this late March and then plant them out in late May, they’ll flower at least a month earlier than normal.