Understanding Blind Canes and Suckers on Knock Out Roses

Two mature Knock Out roses are sending up long, vigorous canes from the base—three feet tall but completely devoid of flower buds. Last year these “blind canes” were cut back, yet they’ve returned. The question: prune again or let them grow?

What Are Blind Canes?

Canes that fail to produce flower buds are called blind canes. The exact cause is debated—climatic factors, light levels, temperature fluctuations, or the plant simply producing more stems than it can support with blooms. However, blind canes are normal and often respond well to a light trim. Cutting them back by about three inches typically stimulates side shoots that will bear flowers.

Could They Be Suckers?

If the Knock Outs were budded onto a rootstock (common with grafted roses), those vigorous basal shoots might be suckers from the understock. Compare the foliage, thorns, and cane color to the original Knock Out growth. If they differ—paler leaves, smoother stems, fewer thorns—they are likely suckers and should be removed at the base. If last year’s pruning yielded no flowers, that’s another strong indicator of sucker growth.

Observe the new growth closely. True blind canes will eventually bloom with minimal pruning; suckers will never match the desired variety and should be eliminated to preserve the plant’s energy.