DEAR JESSICA: My hydrangea has plenty of healthy leaves, but no flowers. It was pruned two Septembers ago. Should I cut it back now or let it be? — Anthony Meule, Valley Stream
DEAR ANTHONY: Your plant is a Hydrangea macrophylla. Pruning it isn't necessary as a matter of maintenance, but when the plant grows too large or becomes misshapen, you can prune it.
Timing is critical because these plants produce flower buds during summer for the next season. Removing them in autumn or the next spring will result in diminished or nonexistent blooming. Prune in late summer, as soon as the flowers fade, but never after September.
When you do prune, remove weaker stems from the base of the plant, being careful to retain several stems of old wood, which will produce buds for next year's flowers.
If your plant had been pruned late last year — or this past spring — buds would have been removed, explaining the lack of flowers. But you say the plant was pruned two years ago, timing that would have potentially affected last year’s blooming, not this year’s. Cold snaps this past winter, however, not only outright killed many plants on Long Island, but zapped flower buds. That very well could have happened to your plant.
In addition, some hydrangeas were killed to the ground, and new growth came from the roots in spring. If that happened, the stems would not have had any buds on them.
I also wonder whether your hydrangea is planted near a lawn that receives fertilizer. Nitrogen lawn fertilizer, which can easily leach to nearby plants, forces plants to direct energy toward growth instead of flowering.
Your plant looks healthy and doesn't appear crowded, so don't prune it this year. In spring, when it begins to emerge from dormancy, apply a slow-release fertilizer product that’s higher in phosphorus than other nutrients (look for a higher middle number in the three-number ratio on the package, ideally something like 5-10-5). That should prime the plant to bloom well next year.
DEAR JESSICA: Can you tell me what kind of tree this is? They seem to be ubiquitous in the neighborhood this year. — John Del Grosso, Islandia
DEAR JOHN: That's a crape myrtle.
I fell in love with these trees and shrubs, often called the "lilacs of the South," in the early 2000s, when I spied what seemed to be a conspiracy of them along I-95 during a road trip to Florida with my family. I also noticed their eye-catching, colorful canopies and mottled brown, orange and cream bark while traveling in Texas. At the time, however, they were an anomaly to me, and, like you, I set out to investigate.
Then, around 2005, while shopping at Costco in Melville, I stumbled upon an army of white-flowered ones near the entrance, and I grabbed one for my garden. I would have preferred pink or purple, but white was all they had — and I hadn't seen them anywhere else.
Cold-tolerant varieties, like the 'Natchez' I bought that day, bloom reliably in our Zone 7 climate. They require little care and offer season-long color. Mine, nearly 15 years old now, has tripled in size and is still going strong, thriving on benign neglect. Once established, crape myrtles are drought tolerant and low-maintenance, requiring only six to eight hours of full sunlight daily to bloom well.
Although many varieties of crape myrtle do perfectly well when planted in the ground, they are not hardy enough to be left outdoors in a container over winter. You might pass that along to your neighbor.
DEAR JESSICA: My tomato plants seemed be healthy, then suddenly began wilting from the top down. The tomatoes also turned brown at their bottoms. Do you have any advice? — Greg Borchik, East Meadow
DEAR GREG: That's blossom-end rot, a condition caused by a calcium deficiency, which in turn is usually caused by uneven watering. It manifests as dark, mushy spots on the bottoms of tomatoes.
To prevent the disease next year, incorporate about 2 cups of dolomitic lime for each plant, worked 8 to 12 inches into the soil before planting. If you happen to have done this in the past two years, you should have your soil's pH tested before amending with lime — and instead apply it at the rate indicated by test results to avoid overdoing it.
Because uneven watering interferes with calcium uptake, it's important to provide 1 to 1 1/2 inches of water in total, accounting for rainfall, per week. For now, if you can find a liquid calcium product (such as Enz-Rot or Rot-Stop), which unfortunately often is difficult to find past early summer, spray plants until leaves are drenched. It won't cure affected fruit, but any fruit that forms will be fine.