Planting & timing · Oct 8, 2026 · By Nell Harding
Dig Your Cannas After the First Frost
Cannas are tender. In a cold-winter garden the roots have to come out of the ground or be lost, and the first frost is the signal to start. Here is when to dig, how to dry and store the rhizomes, and how to keep them alive until spring.
Cannas earn their space all summer with huge paddle leaves and bright flowers. In a cold-winter garden they are also tender, which means the roots have to come out of the ground before winter or be lost.
WAIT FOR THE FROST
Susan Mahr of University of Wisconsin-Madison Extension covers cannas in her guide to storing tender bulbs for winter. Her first rule is about timing: allow frost to kill the tops.
Her second rule is the deadline: do not let them be subjected to a hard freeze, which will turn the stem to mush. The window runs from the first frost that kills the leaves to the first hard freeze.
CUT, DIG, CLEAN
North Dakota State University Extension's advice on storing summer bloomers is to cut off the dead foliage and dig the rhizomes out of the soil.
NDSU then says to wash the soil off the rhizomes and allow them to dry.
Mahr's drying time is short: dry the roots for a day or two before they go into storage.
STORE THEM COOL
Mahr suggests wrapping the cleaned roots in newspaper, or layering them in peat moss or other packing material if your storage conditions are dry.
Store them in paper bags or cardboard boxes at 45 to 50 degrees, she writes. NDSU gives the same range: a box or crate in a room at around 45 to 50 degrees, packed in peat moss or sawdust.
CHECK THROUGH THE WINTER
Storage is not set and forget. Mahr says to check periodically to be sure the roots do not dry out, and to increase the moisture level if necessary.
A root that looks shriveled is the problem she is warning about, and it is far easier to fix in January than to discover in April.
SPLIT THEM IN SPRING
Resist dividing the clump in fall. Mahr's advice is to wait until spring to divide, and to make sure there are at least three eyes on each division.
NDSU notes that cannas can be propagated by separating the rhizomes, leaving at least one eye, or bud, on each piece. Mahr's three eyes per division is the more generous target.
THIS WEEK
Watch the forecast. When the first frost kills the canna leaves, cut the tops, lift the roots, let them dry a day or two, and pack them away cool before the hard freeze.
