Ask the Gardener: Tips for repotting plants and hiding well caps

Ask the Expert Gardening
Planting basil with your tomatoes can repel hornworm.
Planting basil with your tomatoes can repel hornworm. adobe stock

What to do this week Next weekend is the traditional holiday to plant tomatoes and other frost-sensitive vegetables and ornamentals, but global warming keeps pushing the calendar ahead, so you are probably safe to start shopping now for annuals, herbs, vegetables, and container gardens at local nurseries and fund-raising sales. After weeding beds thoroughly, transplant frost-tender seeds, seedlings, and young plants outdoors on an overcast day. If you are in a colder zone than Boston, wait a week or so to be safe. Plant bean and cilantro seeds every two weeks for a continuous harvest. Plant tomatoes in a different location than last year to protect them from diseases in the soil, and settle them 2 inches deeper than they are growing in the pot to increase rooting. Plant basil with them to repel tomato hornworm. Tomatoes labeled “indeterminate’’ will continue to grow all season and need staking, while those labeled “determinate’’ are earlier varieties that fruit all at once and usually do not need it. If cutworms are a problem, encircle the stems with collars of aluminum foil pushed into the soil. Water new plants daily when the weather is hot and dry.

Q. I have been growing a houseplant in my enclosed breezeway for 15 years. Over the past several months, a quarter of the leaves (mostly in the bottom tier) have dried out. It has been in a 9-inch pot for the past five years or so. What could the problem be?

L.K., Acton

A. If the soil dries out quickly, the lower leaves turn yellow, or the roots are emerging from the drainage holes, your plant probably needs repotting. Spring is the best time for this. Select a new container no more than 2 inches wider than your current one, with drainage holes in the bottom. If it was previously used for plants, wash it first in a solution of one part liquid bleach to nine parts water, and then rinse thoroughly to kill any plant diseases. Most plants are easily removed from their pots if you hold them upside down with your hand under the pot and the plant between your fingers. Tap the rim while knocking it out. Cut or unwind any roots revealed to be circling the plant. Slightly moisten some premium potting soil (not soil from the garden), and put it in the bottom of the new container. Adjust and settle the root ball in the middle until it sits an inch below the container rim. Fill in soil around the sides and press it down gently with your fingers. Finish by watering until the water runs out through the drainage holes. Don’t fertilize for a couple of months, as there is usually some already in purchased potting soil.

This is also a good time to put some houseplants outside for a summer vacation of fresh air. Choose a spot protected from too much sun and wind where you will remember to water them, perhaps a patio.


Q. I would like to disguise an 18-inch-tall pipe sticking out of my front yard and reduce the size of my lawn with a large garden bed of shrubs and perennials, maybe even an ornamental tree, but I’m not sure what can be planted safely near the well cap, if anything.

R.Z., Norfolk

A. I applaud reducing the size of your water- and chemical-guzzling lawn, but trees can grow big and so can their roots. Stick with small shrubs and perennials. Consider artificial hollow plastic “boulders’’ designed to cover up such pipes year-round. They also serve as a garden feature to cluster plants around, such as Japanese hollies, smallish and luminously shiny shrubs for sun or shade with black berries for birds. Low maintenance landscape roses, such as the Knock Out strain, give the most colorful flowers for the least effort in sun. Discover Solomon’s seal if you are planting in shade. It can be a revelation. Called Polygonatum biflorum, it is a low-maintenance, well-behaved, and elegant native whose stems arch in the same direction to the same 3-foot height. They dangle ivory bells in May that attract hummingbirds. Even though it is a wildflower, it has the architectural formality of tulips, which makes it great for landscaping. As a ground cover, it resembles tall lilies of the valley, but without the aggressive growth habit. Look for it at the Native Plant Trust in Framingham or at nurseries, but avoid its more common variegated Asian cousin (P. odoratum), which is too short to conceal your well cap and is less impressive.

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