Late summer, fall is best for moving irises, but now is OK

When can I transplant my irises? I would like to move them, and would like to know when is the best time.

— Sherry

The best time to transplant iris is from mid-August into October. However, you can do it now if you need to. The only “problem” with doing it now is that you may not get any flowers this spring. The plants should grow great, establish themselves and bloom just fine for you next year.

I have a large vegetable garden area that has not been used for about three years. Last fall, I threw all the leaves from my yard in the garden area. My plan is to rototill the leaves into the soil. Would this be a good enough soil amendment? Or is there something else I should add? My plan is to make it a flower garden with shrubs, trees, etc. Please tell me what I need to do to prepare the soil.

— Peggy

What you’ve done sounds pretty good to me. The only other thing I might do is to add a little compost to your garden and rototill it in. Most composts have a pretty good amount of nitrogen as well as some microorganisms, which will help in decomposing the leaves you put in last fall. I would expect that those leaves have already started breaking down some, but adding the compost will help speed up the process.

Having the leaves well-decomposed before planting is better for your plants. If you have a lot of undecomposed organic matter in the soil when you plant, it can rob nitrogen from your plants, stunting them.

Also, keep the soil moist, (but not wet) before planting. Those little microorganisms need some moisture to thrive.


The Austrian pines that we planted two years ago are looking yellow and have lost many of their needles in the center of the tree (leaving a bare trunk). What would you suggest I do?

— Janice

What you’re seeing is, in all probability, normal. Austrian pines don’t keep their needles forever. Usually they drop 4-year-old needles. They drop these needles anywhere from August throughout the fall and winter and sometimes even into March.

You can count back the years from the outside tips. Each year is usually (though not always) delineated by a whorl of side branches. So, staring at the tip of the branch, one-year-old growth is down to the first whorl. Two-year-old growth is to the second whorl and so on.

If you find that you’re losing 4-year-old needles, it’s OK. It’s just something the tree does normally.

If it seems that some years your needle drop is much worse than others, it may mean that four years ago that tree had a great year and grew much more than usual. If the tree hasn’t grown a lot lately (which would be normal for a newly planted tree), it may seem like the tree is losing a lot of needles. Again, there’s nothing to worry about as long as it is 4-year-old growth.

Now, if it is more recent growth that’s falling off, it means the tree is under some kind of stress. There are a variety of possible reasons to explain this, but stress is often caused by watering problems: watering too much, not watering enough or perhaps not watering deeply enough. Do a bit of digging down around the tree to see what soil moisture is like.

Another problem that’s been bothering the area lately is pine needle scale. This is a small insect that sucks sap and can turn the needles brown. If you see that on your needles, bring us a sample and we’ll see what we have to help you.

Dennis Hill is the nursery manager at Bookcliff Gardens, Send questions to Bookcliff Gardens, 755 26 Road, Grand Junction 81506; or email .(JavaScript must be enabled to view this email address).


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