Ask An Expert

Need information? Send your question to Cheryl Moore-Gough, Zone 4's Technical Editor for Horticulture. Cheryl is a past Extension Specialist—Horticulture for the State of Montana, and co-authored five books on gardening with her late husband, Dr. Robert Gough.

Send your questions to Cheryl or mail to the address on our contact page. Please include your city and state, as they may have a bearing on Cheryl's answer.

PRUNING TREES FOR CROWN STRUCTURE

Thu, 02/14/2013 - 18:42

I have a 3-5-year-old hackberry and Helena maple growing in the yard. They are10-15 feet high and appear to be healthy. I feel the branches are too closetogether, which presents a poor profile and makes them more susceptible to theviolent winds we get in the Helena Valley. Therefore I would like to thinout some of the smaller branches along the main trunk. My main concern isthat over time, as they get bigger and taller, the areas that were thinnedmight possibly become spaced out even more to the point of looking gangly.

 

The Burr oak has a nice spacing of branches. The hybrid poplar trees in theshelter belt are starting to appear rather spindly due to the spacing ofbranches in the upper portions of the tree. I realize this is a differenttree and probably has these growth characteristics. I am thinking ofwatering them less to possibly slow down their growth rates. I do not fertilize them for the same reason.

 

A new leader (see photo) started on the maple immediately below the existing leader and grew 3-4 feet.  The new leader is now a foot taller than the old leader and substantially thicker at the junction with the trunk.  I am still trying to decide which one to cut to give the best strength in the future.  I prefer the structure of the old leader for future strength.        

         Is it okay to thin the branches on the hackberry and maple?

Pete Schendel
Helena
Montana

 

To answer Pete’s question, we asked Dr. William Hoch, an Associate Professor in the Department of Plant Sciences and Plant Pathology at Montana State University, for his assistance. Here’s what he had to say:

 

Rather than thinning the trees, you should focus on maintaining a proper crown structure, which is the best strategy for promoting long life in trees and preventing damage from stresses such as wind and snow-load. The goal is to maintain a single central leader as high into the crown of the tree as possible, with well-attached scaffolding branches. Most branch failures are due to structural defects, and the two most common defects are co-dominant stems and branches with included bark (you may want to search the internet to see examples of these defects). If branches with one or both of these characteristics have a diameter of less than about 4 inches, you can remove them at the trunk, being careful not to cut flush with the trunk, but to leave the swelled area where the branch meets the trunk, known as the branch collar. If branches with these defects have a diameter greater than 4 inches, it may be better to suppress the branch, which involves removing about one-half of the branch back to an outward-facing bud or shoot. This will cause the branch to grow much more slowly and develop a branch collar; it can then be removed later if necessary. While minor pruning can be done at any time of year, significant pruning should only be done when the tree is dormant.

 

I would definitely remove one of the two leaders on the maple, but there is no definite right or wrong one to remove.  If I had to choose I would say remove the lower of the two leaders that has taken on dominance.  Because this leader currently has dominance there will likely be other shoots that develop below your cut, so you should watch for these and remove them as they grow.  After another year or two the upper leader should have developed full dominance.  

Anonymous

DRIED UP VIOLAS AND PANSIES

Fri, 05/18/2012 - 13:45

Since I am inexperienced with edible flowers like the viola and pansy I am asking if the two edibles that dried up before I could even transfer to bigger pot have a chance of survival. They were in kitchen windowsill and were watered minimally. The container was outgrown and they dried up since I got too busy to transplant; they are now in bigger pot but did not get revived. Should I throw them to compost or should I just cut stems and hope the roots will regrow?

 

Lettuce is now 6 inches tall in a bigger pot but some leaves are drying up despite daily watering by glass window shelf where sunshine on east is received.

 

Broccoli raab is now over a foot high and flowering. At what point does the broccoli flower (green that we eat) come up? The height is getting to need a different place outside the window shelf but I have to wait until June 1 to take it out to porch. What insects or pests bother broccoli in hot weather so I can be prepared?

 

I got fertilizer that is natural good for any veggie in powder form. Should I apply fertilizer once a year or two times a year to the lettuce and broccoli raab?

 

Sage is bigger and spreading horizontally. Basil is 4 inches high and I wonder how it will expand by itself or should I add more roots from external sources to add more leaves?

 

Thanks for your guidance Cheryl.

Trinidad Ponce de Leon
Bozeman
Montana

If the pansy and viola are brown and dry, they are undoubtedly dead. Of course, if you'd like to try to revive the roots, you may certainly do so by replanting them and watering.

 

You may start eating the lettuce any time you'd like, harvesting either one leaf at a time or cutting the entire top, leaving 1 to 2 inches of above-ground stem to regrow. It should regrow once or twice.

 

The broccoli raab can be eaten any time, however, once it flowers it might get bitter. Broccoli raab is a type of non-heading broccoli so if you're waiting for a head to form (like you see with the broccoli in the store) it won't happen.

 

The herbs may continue to grow in the pot, or you can move them to larger ones. The growth habit of sage and basil is different. You may pluck individual leaves from the sage at any time, or nip the tops of the stems to encourage bushier growth. For the basil, you may start using the leaves any time, cutting the stem above a set of leaves. Never remove all the leaves or your plant will die. There is no way to add other roots to make the plant bushier. By pinching the top, more leaves will grow down low. Once the basil starts to flower, remove the flowers to encourage more leaves. But once it starts to flower, it will be close to being done for the year.

—Cheryl Moore-Gough

danspurr

Seed Catalogs

Wed, 03/14/2012 - 09:33

Can you recommend the best seed catalogs for this area?

Tracy L. Livingston
via e-mail

Actually seed catalogs are not that regional; you just need to think regionally when you read the catalog.

The first thing you need to know is how long the growing season is in your location. “Frost-free days” is a little misleading, as the average last frost date and average first-frost date each year can vary by 2 weeks earlier or later.

Consider your season length and select appropriate varieties. Most of us have short growing seasons, so choose varieties that mature relatively quickly. For instance, here in Bozeman, Montana we have an average of 112 days in our growing season, but not every day will be conducive to plant growth. We plant a 63-day corn here to be sure we get corn. While it’s tempting to grow longer-season corn, and we often do experimentally, if we want to count on our harvest, we select short-season crops.

For flowering plants, look in the catalog description for the number of days to flower or days to harvest for vegetables, and purchase varieties with relatively short seasons. You also can grow your own transplants, or purchase them from your local nursery.

Hope this helps!

cherylmoore-gough

Tree Leaves Won't Fall

Mon, 01/30/2012 - 08:51

My mountain ash leaves and one of my apple tree's leaves still haven't dropped, despite being very brown and dry and going through several high-wind days late last fall and through the winter. I've noticed the same in many other yards in town, particularly those with mountain ash and fruit trees. Why are the leaves still hanging on this late in the winter? Does this indicate any potential problem with the tree's health? For fruit trees, does this indicate a potential problem for flower and fruit production this coming season?

Rilla Esbjornson
Bozeman
Montana

When it comes to leaves falling (or not) in autumn, sometimes we can point to a single weather event, such as a quick, hard freeze, while other times we cannot. Leaf senescence and abscission is a result of a complex of issues, including plant hormones, sometimes juvenility, nutrition, drought ,and weather.

 

First, let’s talk about leaf abscission. There is a zone of abscission at the base of each leaf’s petiole. During abscission in a “normal” year it is believed that the balance of the plant hormones from each side of the zone stimulates this layer of cells to divide and to dissolve, causing the leaf to be shed cleanly. A protective layer of cork forms on the stem side of the layer.

 

My first hard freeze in 2011 was September 19, and it put an end to my vegetable garden. Even so, the leaves on the little maple I was given in memory of Bob stayed bright green well into the ensuing Indian summer, while neighboring green ash trees dropped their leaves with a single “foof,” Charlie Brown style. Why the difference? Abscission can be species dependent. Some species’ leaves die in the autumn, but the cells in the abscission layers do not. The process of abscission occurs the following spring, and is similar to the process that takes place in other species in the fall. These are termed marcescent species. But what about non-marcescent species that retain their leaves into the winter? Plant scientists agree it’s complex, and there is no one good reason for it.

 

The leaves of some species of trees will wilt, die, and be retained as a result of drought while other species shed their leaves as a result of drought, even during the growing season. Trees with leaves that are dropped, or that die prematurely, can indeed be stressed. In the natural scheme of things, woody plants reabsorb nutrients from the leaves as they gradually senesce, so there is a possibility of nitrogen deficiency come spring.

 

By the way, there are other reasons trees don’t shed their leaves. If your apple trees have retained leaves on individual branches, inspect the buds and bark to be sure fireblight isn’t the culprit.

cherylmoore-gough

Amending Soil With Blood Meal

Mon, 05/30/2011 - 09:26

 

Last summer we installed a 16' x 28' greenhouse. We added topsoil on the crushed granite. It did well considering the late start and I'm learning a lot about greenhouse gardening. I just had the soil tested (MSE in Butte) and the pH is 7.6; lbs/acre = N:22.4, P:886, K:2160. So they recommended N at the rate of 2 lbs/1,000 square feet. My two questions are: should I add 1 pound of blood meal and can/should I till it into the soil? 

Colleen Hebert
Whitehall
Montana

 

As you know, analyses of fertilizers vary a bit by manufacturer and I do not know what the nitrogen content is of your particular brand of blood meal. If it is 12%, then you will need to apply about 16 pounds of it per 1000 square feet of soil surface area for the approximate equivalency of 2 pounds of nitrogen over that area. Don't till but rather scratch the meal into the top few inches of soil before planting. 

danspurr