5:57am

Fri November 18, 2011
Garden Report

It’s Time for Winter Garden Prep

It’s mid-November and there’s still plenty of outdoor garden work to be done in preparation for winter. KUNC gardener Tom Throgmorton has more.

Most perennials can be cut back in the fall.  But some perennials are better left uncut.  Ornamental grasses, cone flower, Black-Eyed-Susan, and Black-berry Lilies have seed heads with winter interest or winter bird food.  Don’t cut them back until late winter or spring.  We leave our sunflowers up until the birds have gotten all the seed.

The snows did smash some ornamental grasses.  Those grasses can be cut back now because they’ve lost their winter interest.  A power hedge trimmer cuts through most ornamental grasses.  Cut the grass clump about four to six inches above the soil.  Grasses that were not damaged by the storm, like Blue Oat Grass, can be left and cut back next spring.

Hostas have been frozen.  They can be cut to the ground before the next wind blows away their freeze dried leaves.  Trim the ugly leaves off of other foliage plants like brunnera or bergenia.  The other leaves can be left until spring.

Trim other perennials back to their basal leaves.  Asters had a lot of powdery mildew this fall and can be cut to the ground.   

Cut flowering shrubs back after they’ve bloomed.  Autumn is a good time to prune the flowers off of blue mist spirea, Russian sage and summer blooming spirea.  In the spring trim out any winter die back.  Don’t prune spring blooming spirea or lilacs.

Take the tree leaves off of lawn areas.  Over winter the molding leaves will leave dead spots in the grass.  If the leaves aren’t too thick, the lawn mower will mulch them up.

Leaves in perennial and shrub beds don’t bother me unless the trees had leaf diseases during the summer.  The leaves are added mulch insulation.  By next spring the leaves will need to be taken out of the landscape beds and composted.

Pine trees are losing their inner needles.  This is a natural process.  Older needles turn brown and drop during fall and winter winds.  Trees look rough with bunches of brown interior needles.  Austrian and Ponderosa pine lose three year old needles.  By next spring they will only be holding this year’s and last years needles.  Bristlecone pine holds onto five years of needles.

Big, old pine and spruce need extra water going into our driest season, winter.  Soak the entire root zone.  The roots on a forty foot tall spruce grow more than forty feet in diameter around the tree.  Be sure to water as much of the root zone as possible.

tom@throgmortonplantmanagement.com

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