3 Options For Overwintering Canna Lilies Depending On Your Hardiness Zone
Reviewed By DAN ORI
Dan has over 27 years’ under his belt caring for plants and gardens. Working as a Horticultural Instructor and Consultant, he draws on a diverse range of experience that includes working as a Head Gardener, Tree Surgeon, Garden Centre Trouble Shooter, and writer of academic papers. Dan has a Level 3 Diploma in Horticulture and is currently a candidate for the RHS’s most prestigious award – The Master of Horticulture.
Contributions From EMILY CUPIT
Emily is a Gardening Writer, Photographer and Videographer from Derbyshire, UK. She is the Founder of Emily's Green Diary - a community of more than 75,000 people who share in her gardening journey.
IN THIS GUIDE
Cannas are deciduous perennials that are noted for their upright stalks bearing racemes of brilliantly-coloured flowers that pull pollinators in droves.
Now in their native tropical and sub-tropical climes Cannas need no winter care at all but it’s a different matter in almost all of the UK.
These beauties are highly-desirable aliens, having landed on British shores from their balmy and sunny homes in Central America and Equatorial America.
Therefore it is not surprising that they need to be cared for in winter. After all, they are ‘hardy’ only to H3.
| Difficulty | From Easy to Hard, depending on whether the Cannas are in open ground or in containers, and on your location in the UK |
| Equipment Required | As the case may be: gardening gloves, secateurs or hedge shears, gardening fork, gardening trowel or hand spade, newspapers, vermiculite or peat moss, storage box |
Caring for Cannas during winter in the UK will depend on whether you have grown them in open soil or in containers.
If you reside in the sliver of land along the southern and eastern coasts and your outdoor Cannas are growing in a sheltered spot, your task will be much easier.
Overwintering will generally depend on how and where you are growing yours – see all three options below –
1) Overwintering Potted Canna
Before autumn’s first frost or when the plant goes dormant, do as follows:
Step 1) Cut Back
Cut back the foliage and stalks as appropriate for Cannas.
Remember to sterilise cutting implements before using them.
Step 2) Move Container Indoors
Move the container indoors where the temperature will not dip below 12°C.
2) Overwintering Outdoor Plants (Zone H3 Or Warmer)
You can leave Cannas outdoors in Zone H3 (or warmer), particularly if they have been sited in a sheltered spot.
Before autumn’s first frost or when the plant goes dormant, do as follows:
Step 1) Cut Back
Cut back the foliage and stalks as appropriate for Cannas.
Remember to sterilise cutting implements before using them.
Step 2) Water
Give the plant a good watering so that the soil is moistened to a depth of 10-12cm.
Step 3) Mulch
Lay a layer 8-10cm deep of organic mulch around the plant.
Use a mulch made from leaf mould, straw, and such.
Lay it several centimetres away from the base of the plant.
Try to protect the ground from excessive rain, soaking, or puddling.
3) Overwintering Outdoor Plants (Zone H4 Or Colder)
Step 1) Cut Back and Remove the Rhizomes
Please see detailed instructions in our Division guide explaining how to cut back and remove rhizomes.
Bring the removed rhizomes indoors to your workroom, shed, basement, or such.
Step 2) Clean Rhizomes
Gently clean the rhizomes with a soft cloth. If necessary, dampen the cloth.
Step 3) Dry The Rhizomes
Lay the rhizomes on sheets of newspaper spread on a level surface in a dark, temperate room for two to three days so as to dry them out.
Turn them over after a day – the room temperature should be between 13°-18°C.
Step 4) Pack Them Away
Coat or pack each rhizome in vermiculite, otherwise in peat moss, and wrap it in a half-sheet of newspaper.
This will need to be done individually for each rhizome for best protection and storage.
Do this task with dry hands and do not allow any dampness to creep in.
How? Sprinkle a thin layer of vermiculite all over one end of the half-sheet of newspaper. Gently push the rhizome into the canister or container of vermiculite and roll it around, and draw it up covered in vermiculite. Put it on the layer of vermiculite on the newspaper, and wrap it, so that the vermiculite is lifted up with the newspaper as you wrap the rhizome.
Step 5) Box & Store
Put the wrapped rhizomes in an appropriately-sized large but flattish cardboard box.
Do not stack them and try to leave some space between adjacent ones – leave the box open.
Store the box in a cool, dry and dark place, such as a shed; however, the temperature should remain between 7-13°C.
This is where the rhizomes should stay until spring.
When you unpack them, we recommend that you inspect each rhizome for health and viability.
