Fall Pruning

Every fall people get in the mood and want to do something in their yard. The mentality is that you can’t plant because it is too late and you can’t fertilize because it will make things grow and the only thing you can do is cut back stuff, clean up your garden and prune.

You can plant in the fall. Just know that you have to take care of the plants a little differently. You can fertilize. Just know what kind of fertilizer you should be using and why. These two topics are not what we are talking about in this article, but we do have articles that talk about those ideas.

We are talking about pruning and cutting back plants for the winter and putting everything to bed. We treat this like a chore that we think and do only once a year. Most people are like my wife, who I call a tidy gardener. In the fall she likes to cut everything back to the ground, rake up everything in the beds and dispose of all the dead plant material. Most people when they do this, when finished, stand back and look at what they have done with a feeling of accomplishment.

In reality nothing should be cut down in the fall. I heard a old timer once say “If it’s fall….Leave it tall.” I once gave a class on fall pruning which was one of my most signed up for classes. Everyone wanted to know what to prune and when. The reason for the class was because I saw so many people pruning everything down in the fall and then wondering why some of their plants either didn’t come back the following spring or were struggling. You should have seen the faces on the well attended class when I told them nothing should be cut down in the fall. The look of bewilderment was priceless. I went on to explain to the patient crowd the reason everything should be left tall was by cutting everything down you were taking away that plants winter coat. Imagine if you were outside in the winter time and someone took your coat. How would you react? I went on to explain that even though the perennial, shrub or rose looked dead it wasn’t and that the roots were pulling nutrients and moisture down into the roots for storage. The dried up foliage also acts like a coat and breaks the wind, catches the snow which mulches the plants crown and protects the plants foundation.

What about those tidy gardeners and aren’t their neighbors going to look over the fence and label them slobs or worse yet lazy? You can still be a tidy gardener and not cut the plants all the way back. You can cut your plants half ways and cut the rest down in the spring. By cutting them half ways you are still protecting the plant and still have that tidy look.

So knowing fall is not a good time to cut things back…when is the perfect time?

Perennials can be cut back in the early spring. Take a look at how Mother Nature does it and by spring everything is flattened to the ground protecting the roots and providing birds and animals a source of food from seeds and protection from the wind. The end of January or the month of February is a great time for early spring clean up. In Colorado we get nice temperatures to work outside in those months and it gets us off our butts and outside on those beautiful days. Nothing wrong with March and April either if for some reason we can’t get it done.

Cleaning up in the early spring is also a great time to amend a little around each plant with a good compost to freshen the soil around the plant helping with the beneficial bacterias and create some air pockets for the plants roots that has diminished from the compacting of the clay soils. Throw a little slow release organic fertilizer around the plants as you are doing this. You are not going to force the plant to grow too early by fertilizing….Mother Nature does that by warming up the soil in the spring which tells the plants to wake up. There is already food on the table. By adding some fertilizer you are just putting on more food to the table in case there is something that the plant is needing whether it is a micronutrient like zinc or macronutrient like nitrogen. Nothing is going to leach away in our clay soils even if we were to get a lot of moisture, which in Colorado isn’t likely but could still happen. By doing this not only are you outside getting exercise but you are being proactive in the best way so you can enjoy your yard when everyone else is franticly doing their yards.

Shrubs are going to be a different mind set. Pruning shrubs in the fall, if the weather and soil is warm, is going to make it think that it is dying and needing to produce more leaves to get energy from the sun which if the new growth is too tender when the cold hits will get you brown dead tips at the ends of the branches. A dogwood is a good example of being pruned in the fall, getting a couple of inches of new growth then freezing back ending up with brown tips.

So when do we prune shrubs? That depends on what kind of shrubs you are talking about. My rule of thumb, and I’m sure there are exceptions, is if it blooms in the spring, prune it after it blooms. Pruning spring blooming shrubs in the fall will result in fewer or no blooms. The bloom buds have already set the previous late summer and by fall pruning you are cutting off your blooms.

Examples of spring bloomers are forsythia, spring blooming spirea and lilacs. Summer or fall blooming shrubs can be pruned in the early spring. These shrubs bloom on new wood. Examples are butterfly bush, summer blooming spirea, Russian sage and althea. Just think of when it blooms and let that be your guide line.

Trees should be pruned when the sap is at its lowest which generally is December and January.

Grasses should be cut down in the spring. You grew the ornamental grass for the tassels. Enjoy them as long as you can. Cut off the broken stems as they break. The tassels are great winter interest and the fish feed on the heads. I’m checking to see if you are still reading…the birds will feed on the seed heads.

Now if you are still the tidy gardener and want everything cleaned up, that is ok. After you have cleaned up everything, buy some compost or mulch and use that to mulch your plants roots. It will just cost you a little more than using what you have.

Everything is going to need a drink in the winter to keep everything hydrated. Try and give everything a drink one or two times a month while everything is dormant. When the snow falls if it is over 3 inches that would be considered a drink Anything less than 3 inches usually evaporates before it has a chance to soak in. If it has been too cold and the ground is frozen…pass on the watering or you will have a frozen mess.

One example of me wanting to cut my perennial back to the ground would be if I had a problem with a fungus or bug like a spider mite that I couldn’t control. Cutting them back lets Mother Nature take care of the problem I couldn’t. By not pruning back the good and the bad bugs will use the plants as winter protection also.

Fall and early spring before the emergence of the plants is also a good time to do a little preventive bug and fungus control. Once a hard frost has hit and the leaves have fallen is a good time to use sulfur dusts and oils to get rid of and smother fungus and bug eggs sitting there dormant until spring. Sulfur dust is a good organic way to prevent fungus around the plant and the oils are a good way to spray on shrubs and trees to prevent any unwanted bugs or fungus wintering over on your plants. The oils I like to get people to use once in the fall and the other time in the early spring before the plants come out of dormancy.

Sometimes the early spring application can’t be done because of weather so at least you have the fall application to help. Pruning in the fall may not kill a plant especially a well established one but, doing it at the right time well help with the overall health of the plant. Gardening in the fall and winter is a great way to be proactive. Use Mother Nature as your guide line. She will help you be successful.