Fielding Questions: Hibiscus leaves yellowing, should you stress an apple tree, grass seed longevity
This week, gardening columnist Don Kinzler fields questions on hibiscus plants, beating apple trees and how long grass seeds will last.
Q: Can you tell what might be the problem with my hibiscus? It’s losing leaves every day. I did try fertilizing it in case that’s what it needed. – Patty F.
A: Overall, the hibiscus’ health looks very good. The leaves are of normal size, and the color is a rich green. The newest growth on stem tips looks well-formed and not spindly, which indicates that it has gotten decent light or sunshine this winter.
From the photo, I notice the plant is in its original nursery-style black container, which is set inside the outer clay-colored pot. Although the hibiscus is doing well, it’s likely running out of root room and nutrition. As the days are getting longer, fertilizing will help, but it needs a larger pot also.
I’d suggest removing the hibiscus from its nursery-type container and repotting into a pot at least as large as the outer one in which it’s now sitting. Use high-quality potting mix that contains a slow-release fertilizer.
Loss of leaves on overwintered hibiscus is normal, and I think repotting yours will keep it healthy, now that days are getting longer and spring is somewhat closer.
Q: Have you heard of beating a young apple tree with a broom in the spring to get it to produce apples? It’s a rumor going around. – Scott K.
A: Beating a slow-to-bear apple tree with sticks and chains is an old tale that keeps resurfacing. The idea behind it is to stress the tree, and many trees when stressed will bear fruit and seed as nature's instinct to perpetuate the species.
Although trees under stress might bear fruit at a younger age, it's not healthy, and commercial fruit growers would never do this to their trees to coax them to bear fruit.
Commercial apple growers will in fact remove fruit from young trees that attempt to bear earlier-than-desired, so the energy can go into structural formation of a good, well-branched tree that will last many decades. Depending on apple variety, most types require five-to-seven years before bearing. Some, such as Haralson, require up to nine years. If apple fruits form before their optimal time, it's usually best to remove the fruits before they reach dime-size.
Lawn fertilizer can delay normal age of fruit production, so keep lawn fertilizer away for a distance equal to at least the tree's height in all directions from the trunk. The roots extend outward for at least one-to-two times the tree's height in all directions.
Waiting for an apple tree to bear at its optimal age is better than unnaturally stressing a tree into bearing, which might cause long-term health problems.
Q: I’ve got some leftover grass seed from last year. Will it still be good this spring? – Nate L.
A: Whether holdover grass seed will still germinate at the original rate depends greatly on how it has been stored since last use. Many of us are guilty of putting the leftover package of grass seed on the garage shelf after using, where it’s subjected to the garage’s heat and humidity all summer long. Such storage usually reduces the germination rate.
The best storage for grass seed is in a tightly closed container in a cool, dry place with temperatures between 40 and 50 degrees Fahrenheit. If grass seed has been exposed to the heat, humidity and fluctuating temperatures of a garage, germination might be reduced. To compensate for less germination, spread the seed at a slightly higher rate than indicated on the package.
Grass seed germination also diminishes if stored for multiple years. Even with proper storage, several research studies indicate the germination rate decreases to less than 50% after three to five years.
If you have a gardening or lawn care question, email Don Kinzler, NDSU Extension-Cass County, at firstname.lastname@example.org . Questions with broad appeal may be published, so please include your name, city and state for appropriate advice.