How to Divide Bulbs

Clump of Hyacinths that require dividing

Spring flowering bulbs are a set-and-forget kind of crop, but after a few years, they’ll benefit from being lifted and divided. In this article, we’ll discuss how to divide bulbs, the reasons for doing so, how to store bulbs in Australia, and much more.

Why Divide Bulbs?

Most bulbs multiply annually, creating offshoot bulbs or clusters around the originals. However, after a few years, this can lead to overcrowding and competition that can affect growing performance and flowering. By dividing your bulbs, you give them more room to grow, and as a bonus, you end up with free bulbs to expand your garden.

When to Divide Bulbs

There are a few signs that your bulbs may benefit from lifting and dividing, such as:

• Reduced flower production.
• Unusual or uneven growth.
• Clumping behaviour.

Any of these are likely to happen every three to five years, but you can pre-empt this by dividing your bulbs before they show any of these signs.

The best time to lift your bulbs is after the foliage has fully died back. Bulbs rely on the foliage to feed energy into the bulb for next year, so wait until this has occurred before disturbing them.

All spring and summer flowering bulbs can be divided, and garlic, echalion, shallots, and potatoes can be divided and replanted for next year’s crop.

For spring flowering bulbs such as daffodil bulbs, tulip bulbs, jonquil bulbs, hyacinth bulbs, anemone bulbs, crocus bulbs, freesia bulbs, and ranunculus bulbs, lift in early summer around December/January.

For summer flowering bulbs such as bearded iris bulbs, calla lilies, canna lilies, dahlia tubers, gladioli bulbs, hippeastrum bulbs, Lilium bulbs, oriental lilies, and peony roses, lift in early winter around June.

How to Divide Bulbs

1. Once the plant's foliage has died off, grab your garden trowel and dig around the bulb about 7cm out from the bulb to avoid damaging it.
2. When the soil around it is loose, you can dig underneath.
3. Using your hands, gently lift the bulb out of the ground.
4. Gently separate the ‘child’ bulbs from the ‘parent’.
5. Check for damaged or diseased bulbs and discard any that are soft or rotten.
6. Replant your parent bulbs in their current position and plant out the child bulbs, leaving the recommended spacing between bulbs.

Note that the smaller ‘child’ bulbs won’t be as productive as their parents until they are more mature, so they may take a season or two to establish themselves and start flowering.

How to Store Bulbs in Australia

If you plan on storing your bulbs until the next planting season, dust off as much soil as possible, let them air dry for a few days, and then store them in a breathable bag with something dry and sterile like sawdust or coir. Then, place them in a cool, dry, dark place and check them occasionally to ensure none are rotting.

Do I Need to Store Bulbs Once Divided?

Climate and soil conditions will dictate whether you can leave your bulbs in the soil all year round or not. In most southern Australian states, you would be safe to leave bulbs in the ground for the entire year, except in the conditions listed below. For more tropical or extreme climates, we recommend lifting your bulbs.

Wet soil can cause bulbs to rot, so if your garden beds are prone to holding too much water, it may be safer to dig up your bulbs and store them between seasons. Cool climate bulbs such as tulips don’t cope well with hot conditions and may die if left in exposed positions during summer, so lift and store them if you live in an area prone to hot summers.