Cutting back your garden for fall

We have had our first hard frost and now comes the hardest part of fall – cutting back my garden.

Some people cut their plants back and clean up the garden all at once. I prefer to do it gradually, for a couple of reasons: it helps me adjust to the change of appearance, and not everything dies at the same time.

There's freeze damage on my tomato, but the undamaged
yellow calendula (pot marigold) will continue blooming for
several weeks.

The process of garden clean-up is most important if you have insect pests, like aphids or spider mites, or diseases, like powdery mildew. Those perennials and annuals should be cut back to the soil line early and thrown away. Insect pests often winter over in the soil and plant debris – like dead leaves – around the plants and are ready to re-infest your plants when the weather warms up.

I read a book from the series by Ellis Peters called Brother Cadfael about a 12^th century English monk who solves mysteries using plants. It is a fun read if you are botanically inclined and like historical fiction. One of the ideas I retained from his musings is to leave the roots in the soil when you clean up a garden. This is especially good advice in my heavy clay where I am trying to get more organic materials into the soil. So I cut off my annuals rather than digging them up. In the spring, I plant around the old roots and let them continue to break down.

I think the vegetable garden should be the space that gets the most attention. Plant debris from veggies should be thrown away, not composted. This may be contrary to composters’ point of view, but a clean veggie garden makes for a healthier space next season. By all means, add more organic materials to the soil - till in tree leaves or add well-aged compost. But don’t use your vegetable waste here.

It is a common practice to plant tomatoes in different locations every year so that diseases from previous years don’t infect your new plants. So I am careful to pull up my tomato plants to remove the majority of the roots.

In the rest of the garden, I am less meticulous; although I always clean up as well as I can when there are obvious problems. It is harder to prevent overwintering pests in flower beds where there is a mulch, but it is still worth the effort to remove plant debris.

I mentioned that I gradually cut back the stems. This is on my perennials. As the plants go into winter dormancy, they store the food that their leaves are making in their roots; or stems and roots for trees and shrubs. Like hibernating bears, storing this food makes it possible to survive the winter and resprout in the spring. By cutting off green leaves and stems that are still photosynthesizing (making food using the sun), you are decreasing the food storage capacity of the plants. This is the same reasoning behind letting your tulips and daffodil leaves go completely brown in the spring before cutting them off.

I also leave stubble in my flower beds, unlike my vegetable garden. I cut stems 5”-10” above the ground on everything that isn’t diseased. The stubble acts as a miniature snow fence. Our snow is often melted on our wonderful sunny days but I want to keep as much as I can around the plants. These stems slow the melting by casting a bit of shade. They also slow down snow movement if there is wind and keeps the snow around the base of the plant.

Snow acts as an insulator and helps keep the soil at a constant cold temperature, which is good for the plant roots. A spell of a few weeks of sunny weather can warm the soil and fool the plants into new growth, even though it is still winter.

I don’t cut my ornamental grasses back until spring. I love having something to look at in my garden through the dark days and the grasses provide great winter interest. I have 8 different species in my small garden, 8 different seed heads and growth patterns to look at.

 

My process of gradually cutting back the garden may not work for everyone, but I believe it makes for stronger growth in the spring. Leaving stems means I have to cut back the dead stems again in the early spring, but I am out there anyway, cutting back the grasses. This helps me scratch the itch of needing to garden, even when there will be several more weeks of freezing nights.