How to eliminate onion grass, prune a wayward cherry tree and blanch celery

DEAR JESSICA: Something was wrong with my celery last year. As it matured, the stems became hollow. The plants looked very good and healthy otherwise, but the celery had such a strong taste that I didn’t care to use it. My garden has been organic for over 20 years.

— Ingvor Johnson,

Setauket

DEAR INGVOR: Having grown organically for 20 years, you clearly are an experienced gardener, but I have to ask: Are you sure you planted celery and not lovage? Sometimes seeds get mixed up and starter plants get mislabeled, so I’m wondering if that’s possible. Lovage is a plant that somewhat resembles celery and has a flavor reminiscent of celery and parsley, only stronger. Also, its stem is thin and hollow.

Having called attention to that possibility, we also need to consider whether your celery has simply turned bitter. You don’t mention whether you’ve ever grown celery before, but if you haven’t, my guess is that you might not be aware of the best growing practices, without which your plant will not taste like the celery you’ve come to expect.

As celery grows, it prefers full sun and requires regular fertilization and consistently moist soil. As plants mature, however, they should be shielded from sunlight in order to block the production of chlorophyll, which would cause stalks to toughen and intensify their flavor. To prevent this, growers “blanch” their plants.

Blanching involves wrapping stalks two weeks before harvesting with cardboard, newspaper or a paper milk carton, and tying or taping it into place, as needed. The barrier prohibits sunlight from reaching the plant, which slows photosynthesis and results in lighter-colored, tender stalks. The commercially grown celery that’s available at your supermarket has been blanched on the farm.

DEAR JESSICA: Is there any way to get rid of the wild onions that have spread throughout my lawn without killing the lawn?

— Christopher Paul,

via email

DEAR CHRISTOPHER: You don’t say how extensive the infestation is, but if at all practical, the most effective means of eradicating wild onion is by hand, using a trowel.

To complicate matters, the weed’s root system is composed of bulblets that aren’t active at the same time: some will sprout and grow this year while others will remain dormant, and those, in turn, may not become active until next year or the year after that. Leaving any behind will ensure regrowth — but possibly not for a few years. Still, if necessary, a few repeated digging sessions should do the trick.

If digging is impractical, chemical herbicides can be used. Be sure to buy a product that contains a “spreader sticker” ingredient, which is a surfactant that helps the liquid adhere to the plant’s glossy stems. Be sure to follow package instructions closely.

To increase absorption, it’s best to bruise plants before spraying by stepping on them. That will open up a wound through which the herbicide can enter.

As you feared, products that would be effective, such as Roundup Weed & Grass Killer, will also harm surrounding plants, including your lawn and even trees, so you’ll need to apply it to each individual weed with a small sponge. Some folks skip the stomping and apply the product with steel wool, which injures as it coats. Be sure to wear rubber gloves when applying herbicides in this manner.

Because of the staggered life cycle of the bulbs, you’ll likely have to repeat the process in November and again next year as dormant bulbs sprout.

DEAR JESSICA: I have a 2-year-old Kwanzan cherry tree that appears to be very healthy. My question is about how and when to prune this tree. It has grown very long shoots (3-4 feet) that look very fragile. Any help would be very much appreciated.

— Paul Hartmann,

Wantagh

DEAR PAUL: Spring bloomers like your Kwanzan cherry should be pruned immediately after flowering. Pruning earlier would risk removing buds before they bloom.

When pruning, remove any branches that are too long or crisscrossed, taking care to retain the tree’s natural shape and form. Those undisciplined branches should be cut on the diagonal to 2 inches from the main trunk. If you are simply shortening some branches, they should be cut just above a healthy bud.

Branches smaller than a quarter of an inch in diameter can be cut with sharp hand pruners; those between a quarter of an inch and 1 1⁄2 inches will require loppers. Thicker branches should be cut with a saw, but it doesn’t appear your tree is that large.