Gladioli – Lifting and Storage

Why lift gladioli each season?
Today’s hybrid gladioli are bred from species which are native to parts of South Africa where there is good summer rainfall and dry, mild winters.  This is why they have adapted to flowering in summer, when moisture is available for growth.  The dry, mild winters allow the corms to become dormant and harden off in the soil.

In New Zealand we don’t have dry mild winters, and if we want to save the corms for flowering next year then we need to lift them each year in autumn.

If the corms are left in the ground, then it’s survival of the fittest!  The weaker varieties will die out in the cold wet soil, and the stronger varieties will increase rapidly in the extra space.  This gives rise to the common misconception that gladioli change colour.

When to lift.
About six to eight weeks after flowering is the most suitable time.  By this time the new corm will have developed well, and there should also be plenty of small cormlets which you can use to increase your stocks.

You should not wait for the leaves to die back; it is far better to lift the corms when the leaves are still green and healthy.

Lifting, curing and cleaning.
Loosen the soil with a fork and, grasping the leaves of the plant firmly, pull the whole plant up out of the ground.  Take care to remove all the little cormlets too, you may want to keep them to build up your planting stock.

Trim the leaves off level with the top of the corm, remove any large pieces of 

soil attached to the roots, and place the corms and cormlets  in a breathable container such as a paper bag.  Discard all the leaves and other plant material.  Leaving it in the soil will allow a build up of diseases which may make it difficult to grow gladioli in the same place again in future.

Put the bags of corms and cormlets into a warm, airy place for two to three weeks.  A hot water cupboard is ideal.  When they are thoroughly dried and cured, you will be able to remove the dried roots and the old corm easily and cleanly from below the new corm.

Clean the new corms up, and remove a layer or two of skin to ensure that they are healthy underneath. 

Winter Storage
Once the dormant corms are clean and have been inspected for disease, they should be stored in a cool airy place until planting time in spring.  Storage in a warm position will result in breaking the dormancy too early, before conditions are suitable for planting outdoors.

It is a good idea to dust the corms with some insecticide powder before storage, to ensure that no insect damage occurs over winter.

New Zealand Gladiolus Society
New Zealand has an active gladiolus society for those who are interested in learning more or getting involved in showing gladioli.  The contact for this is Mr. Colin Jamieson, Secretary NZGC, 11 Kaikomako Place, Lyttelton, Christchurch.  Subscriptions are only $10.00 per year.

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