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Don Kinzler, Published October 11 2013

Fielding Questions: How long does smoketree take to establish?

Q I have a four-year-old royal purple smoketree that is doing nothing. I see other beautiful examples. Does it take years to establish? Any suggestions?

– Sherry Zueger, Moorhead

ASmoketree is also known by the common name smokebush. The scientific name is Cotinus coggygria. Its loose clusters of flowers give the appearance of clouds of smoke, hence the common name.

Many of its available cultivars are hardy in zones 4 to 5 and are borderline in hardiness for our zone 3 to 4 northern regions. The tops frequently die back, but growth comes back quite nicely from the base. Rather than growing into small trees in our region they tend to be shrub-like.

Smokebush is best located in full sun in a protected microclimate location that receives good winter snow cover. After four years it should be “smoking” if the location is right.

Royal purple doesn’t bloom on “new wood,” so some of the branches need to survive winter.

The purple-leaf variety nordine tends to be hardier than royal purple. One of the hardiest smokebush cultivars is cotton candy, a closely related species with bluish-green leaves and pretty pink “smoke” and hardy into zones 3 to 4. I have seen cotton candy in the nursery trade, and it is beautiful.

QI’ve been told that I need to prune my raspberry bushes back to ground level this fall. Is that true?

– Amanda Nicholson, Fisher Minn.

ARaspberry pruning tends to be confusing for us gardeners, and it depends on the type of raspberries you have.

Within the patch there are several ages of growth: current season canes that grew from the roots this spring, canes that are two years old, and older canes if they haven’t been pruned out. Summer-bearing varieties bear fruit on canes that are two years old and then the canes die. In the fall, prune back to ground level the old canes that bore fruit. They are easily identified by their dark brown, woodier appearance.

Everbearing varieties like heritage are capable of producing a summer crop on two-year-old canes, plus a late crop on the current season’s canes.

Everbearing varieties can be pruned the same as the summer-bearing types by cutting out two-year-old canes that bore fruit. Or you can prune back everything to ground level, and because they produce fruit on new growth, you will get one large later crop next year.

I’m thinking of replacing my own heritage plants with the variety Redwing from the University of Minnesota because it is nearly two weeks earlier.


If you have a gardening or lawn care question, email Don Kinzler at ForumGrowingTogether@hotmail.com. Questions with broad appeal may be published, so please include your name, city, and state for appropriate advice.