Perennials and Winter

This is such a great time of year - the kids are off to school, the veggies are showing the results of all the Summer's hard work and the pressure to keep up with the Jones' garden is easing up. Back to being a happy housebound garden-book reader.

But before I settle into my over-stuffed chair with a good book, I really must get the perennials ready for their long winter's sleep.

In an earlier posting, I said that I leave my Blue Oat Grass up all winter, preferring to pull out the dead leaves in Spring.  I've found that the seedheads look really nice waving gently in the winter breeze and snow balances very prettily on the thin blue leaves.  But the Karl Foerster Grass needs to be cut back since it's huge and impossible to "de-leaf" in the Spring the way I clean up the Oat Grass.

So I'll snugly tie a length of garden twine around the leaves of the Feather Reed Grass about 6" above the ground and cut the grass with hedge clippers. In the Spring it'll be easier to clean out any dead leaves when the new ones emerge from the clump.

The Peonies are fading fast so I'll cut them down to the ground. The Roses can be trimmed down to keep the canes from whipping around in the winter wind and breaking.  I usually leave about 8 or 10" since my Roses are growing in a protected area but many gardeners will wrap their Roses in burlap and mound mulch or soil around the bundle.

Some people trim their Lavender in the Spring but I've found it's easier to get the flower "wands" trimmed off in the Fall since the new growth in Spring comes up right in middle of the old stems. I'm carefully to not disturb the woody stems which will produce next Summer's flowers. There usually are some old dead branches underneath so I clean them up while I'm there. It also gives me a chance to evaluate the plant and look for any new starts that have sprouted over the Summer. By next Spring or Summer, I may be able to cut them free of the older plant and move them to a better location.

The Butterfly Bushes need to be cut back hard - in many parts of Oregon, it's an invasive plant but here in the High Desert we just need to prune it hard in the Fall to keep it under control. Mine have been growing about 8 years so I prune them down to about 12". When the early Summer growth appears, I often trim them back again, pruning out old branches then.

The Forsythia, the Hibiscus and all the Spireas will stay un-pruned for now - in the Spring I can see where any damage was done by the Winter and cut back to green wood then.

Once I've done the Performance Review of the plants and cleaned up fallen leaves and branches, I'll get the hose out again and do some heavy watering. So many plants suffer from the drying cold winds of Winter unnecessarily - dragging out the hose every 6 weeks will prevent a lot of dieback next Spring. If we get a few good snowfalls or some timely rainstorms, I'll mark my calendar and check the soil again in a month.

Many of us remember that the past couple Winters have brought shockingly cold temps - minus 25 and below! With temps like that, we really can't determine what Hardiness Zone our plants are living in. And as much as I'd like a greenhouse that encloses my entire yard, it just isn't practical (and my hubby won't agree to buy it for me - imagine that!), I'll have to use other methods to protect my perennials and trees.

Toasty warm decomposing compost (cornell.edu)

So I turn to mulch.  Once the plants are trimmed, the ground beneath them is cleaned up and well watered, I can put down a nice 4 or 5 inches of mulch. I use either ground bark from a landscaping company or the aged compost from Knott Landfill, making sure to keep it back a bit from the trunks of any plants. (The insects are looking for a good, warm place to over-winter in safety and a shrub with mulch against the trunk is ideal.) In the Spring, I'll turn the mulch into the soil as an amendment.

That should do it, my plants are as ready as I am for the winds to blow and, I hope, the snows to fall.

More information about mulching is here: http://extension.oregonstate.edu/deschutes/sites/default/files/Winter_Care_of_Perennials-reference_list.pdf