Ciscoe Morris, Seattle Times garden writer, offers tips on protecting plant roots through the winter; selecting Katsuras as street or shade trees and harvesting pumpkins.

Applying 3 inches of mulch on the soil surface in fall protects plant roots from winter cold and prevents rain from compacting the soil surface. My two favorite mulches are wood chips and compost.

Wood chips, available from local arborists, are the best choice for areas where you rarely move plants because, as is true of any raw organic substance, it will rob nutrients if mixed into the soil. Left on the surface as a mulch, wood chips give great weed control and break down slowly to form fantastic topsoil.

Since compost is already broken down, it works fine in areas where you plant or transplant and it will actually improve structure as it gets mixed into the soil.

Compost doesn’t prevent weeds, but it makes them much easier to pull. Of course, once plants go dormant, the premier mulch to use is highly nutritious, freshly washed cow manure.

Unlimited Digital Access. $1 for 4 weeks.

Make an appointment with the marriage counselor before you have it delivered however, because if it doesn’t rain steadily to dilute the pungent odor, the long lasting essence of Iowa is going to get you into big trouble with your partner.

A street tree with year-round interest

If you’re looking for a shade or street tree, Katsura (Cercidiphyllum japonicum) is a beautiful choice. If you’ve got room for a big tree, the standard Katsura can eventually reach 60 feet tall and 30 feet wide, but if you don’t have room for a honker, ‘Heronswood Globe’ is a dwarf selection with the same qualities, yet reaches at most 20 feet.

Katsuras have something to offer in every season. The sculptural branching and shaggy bark add winter interest. In spring, the nearly round leaves emerge reddish purple, and then mature to an attractive bluish green in summer. The best is reserved for fall when the foliage not only turns glorious shades of yellow and orange, but also emits a wonderful fragrance on warm summer days.

Most folks say it smells like brown sugar, but the aroma reminds me of my childhood in Wischeescin when neighbors cooked down maple sap to make syrup.

Katsura trees are hardy to 30 degrees below zero and perform best in well-drained soil and full sun. Mature Katsura trees usually require only normal watering but newly planted trees, especially if planted in a hot windy location, may require extra moisture for the first couple of years until they become well established.

Don’t get tricked by pumpkin harvest

I’ll never forget the year that I challenged the gardeners I worked with at Seattle University to a pumpkin-growing contest. The prize for the biggest pumpkin was a stash of extra large peanut-butter chocolate-chip cookies, one donated from each contestant.

The pumpkin I grew turned into a real honker and I annoyed my fellow workers by bragging about it every day. Imagine my surprise when I sauntered out to harvest big “Gloria” only to find that she was missing, replaced by a can of pumpkin-pie filling! Don’t let Mother Nature pull an even worse trick on you.

It only takes a week or two of temperatures below 50 degrees to rot a pumpkin when it’s growing on the vine, so to be safe, harvest as soon as the rind turns hard and the skin turns orange. To make sure it keeps well, leave at least 3 to 4 inches of stem when you cut it, and store it in a dry, warm location with temperatures between 55 and 70 degrees.

If you’re in a pumpkin contest, I strongly suggest you guard it in your bedroom the night before the weigh-in!

Ciscoe Morris:; “Gardening with Ciscoe” airs at 10 a.m. Saturdays on KING-TV.