Q: I’ve attached photos of two long-needled evergreens in our backyard. During the past three to four weeks, the needles started to turn brown and drop off the trees. Any thoughts about this sudden change to the two trees? — Gary Lee, Casselton, N.D.
A: The browning of the interior needles on your Ponderosa pines is normal shedding of needles that happens on pines and other evergreens as older needles cycle out. Even evergreens shed needles at some point, except they do it in cycles instead of all at once, so the tree is never left totally bare, as when deciduous trees lose their leaves. The normal shedding of pine needles is what we see on the floor of pine forests. As long as the needles on the tree’s exterior appear healthy and buds at the tips of branches are plump and fresh, as they appear on yours, there’s no need to worry.
The brown needles will continue to be shed, and as new growth occurs next spring, the inner needles won’t be missed. Mulching around the trees with shredded bark would be a good step, which will reduce grass competition and greatly speed the trees’ growth.
Q: I notice that spruce often produce more cones certain years. Is that a result of stress on the trees? We have evergreens that are loaded with cones this year — more than usual, and I wondered if it was a result of our dry July and August. — Kathleen Johnson, Langdon, N.D.
A: Stress can be one cause of heavy cone bearing, as part of a tree’s natural survival instinct to perpetuate the species. In the case of spruce, though, cones are produced in a two-year cycle, in which cone buds are formed one year and then develop and mature the second. So this year’s heavy cone crop wouldn’t be in response to this year’s dry weather, but instead possible stress last year that initiated the cone formation.
Stress isn’t the only cause of heavy cone formation. Conifers exhibit cycles, bearing cones heavily every so often. Many tree types do this, forming heavy seed crops from time to time, sometimes in response to past growing conditions, but trees are also believed to occasionally seed heavily as part of their natural instinct to periodically litter the countryside with potential new offspring.
Q: My lawn is on clay soil and since we started the lawn three years ago, I've been adding gypsum three times a year in hope of amending the soil a bit. My lawn looks wonderful. Is gypsum a good addition? — Sally Brovold, Bismarck, N.D.
A: Gypsum’s chemical name is calcium sulfate. Its benefit to our region’s soil is limited to treating soils termed sodic, which is a soil chemistry term meaning there’s excess sodium at the molecular level. Sodic soils are more intense than saline soils, which is the soil chemistry term for soils having high soluble salts, not necessarily sodium.
North Dakota State University’s soil scientists caution that gypsum should be used only to remedy soils that have been determined to be sodic, with high sodium content. NDSU reports that gypsum generally does not benefit soil the way that additions of organic material do. For soil improvement around the yard and garden, adding compost, peat moss or manure will improve soil texture and health.
To decide whether to continue adding gypsum to your lawn, an important first step is to get the soil tested, which is a simple procedure. In Bismarck, contact the NDSU Extension Burleigh County office, and they can tell you how to submit a sample to the NDSU Soil Testing Lab. The results will help you develop a plan for future fertilizing or soil amendment.
If you have a gardening or lawn care question, email Don Kinzler, NDSU Extension-Cass County, at firstname.lastname@example.org or call 701-241-5707. Questions with broad appeal may be published, so please include your name, city and state for appropriate advice.