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  • May garden tips & tasks

    GARDEN EVENTS IN MIDDLE TENNESSEE

    May 20: Master Gardeners of Davidson County Urban Gardening Festival, 9 a.m. - 4 p.m., Ellington Agricultural Center Demonstration Garden. Free admission. www.mgofdc.org; on Facebook at www.facebook.com/mgofdc.

    June 10: Middle Tennessee Daylily Society show and sale, Ellington Agricultural Center’s Ed Jones Auditorium, 440 Hogan Rd. in Nashville. Sale open at 10 a.m.; show opens to the public at 1 p.m. To learn more about the Middle Tennessee Daylily Society, visit www.middletndaylilysociety.org.

    It’s time to plant those tender herbs and vegetable transplants, such as basil, dill, tomatoes, green peppers, hot peppers, eggplant.

    If tomato transplants are already too tall and leggy, you can plant them on their sides and cover the long stems with soil. The stem tips will turn upward, and the buried stems will sprout roots.

    Sow seeds of bush beans and pole beans, cucumbers, sweet corn, melons, okra, field peas, pumpkin, squash and zucchini. Follow the directions on the seed package for planting depth and spacing. Vegetables grow best in full sun.

    Cut the faded blossoms of peonies. Fertilize the plants lightly in late spring or early summer.

    Remember the basics of watering: morning is best, so plants’ leaves have time to dry before evening. Lawns, perennial borders and annuals like to have 1 – 1½ inches of water per week.

    Many indoor plants enjoy a summer vacation outdoors. Give them a cool, shady spot in the yard, and don’t forget to water them.

    Prune thyme frequently so it will stay full and green in the center.

    Weeding is easiest after a rain. If the ground is too dry and you need to weed, soak the bed first with a hose or sprinkler.

    Whether they’re growing in the ground or in pots on the porch, pinch the tips of geraniums from time to time to encourage them to branch out and to produce more flowers. Geraniums in pots benefit from regular feeding with a water-soluble fertilizer.

    Remember that mulch can be a gardener’s best friend. Pine straw or composted leaves are good alternatives to hardwood mulch.

    Harvest herbs as they reach their peak. Dry small leaves on a screen, hang small bunches of long-stemmed herbs in a warm, dry room out of the sunlight.

    Plants growing outdoors in containers dry out quickly when it’s hot. Check them daily, and water as needed.

    Don’t go near hydrangeas with the pruning shears unless all you’re cutting is dead branches. If the bigleaf hydrangeas look like they’re not going to bloom, it could be that the buds were nipped in a late cold snap, or the plant was pruned too late last year.

    As the flowers of Shasta daisies begin to open and then to fade, keep them clipped off. This prolongs the blooming season of daisies (and most other annuals and perennials), and keeps the plants looking better, as well.

    Watch for aphids on shrubs and perennials. A strong blast of water from a hose will remove many of them, or spray with insecticidal soap.

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Hydrangeas’ color depends on the soil

My hydrangeas have pink flowers. Is it true I can make them change to blue? How do you do that? Can I also change my white hydrangeas to pink or blue?

Hydrangea-blueThe French hydrangea (Hydrangea macrophylla) is the one with the big, round, blue or pink clusters of flowers. The color of the flowers depends on the pH level of the soil – how acid or alkaline it is. French hydrangeas growing in alkaline soil have pink flowers; if the flowers are blue, that indicates that the soil is acid.

There’s a lot of science surrounding the explanation of soil’s pH that involves discussion of hydrogen ions in the soil – way beyond the scope of this column. One simple thing to remember is that pH is measured on a scale from 0 to 14; pH 7 is neutral, below 7 is acid, above 7 is alkaline. You can learn your soil’s pH level by having the soil tested at your county’s extension service.

You can change the soil’s pH level (and therefore, the color of the French hydrangea flowers) by adding lime to the soil, to make it more alkaline (pink). Add aluminum sulfate, to make it more acidic (blue). How much of either amendment to use depends on the soil type and current soil pH – a good reason to have the soil tested before you proceed.

The change doesn’t take place right away. Changing the pH of the soil this year will mean changing the color of next year’s blooms.

Soil pH doesn’t affect the color of white hydrangeas such as Annabelle (H. arborescens) or oakleaf (H. quercifolia). Their flowers are always white, though as they age, Annabelle flowers take on a green tint. Oakleaf hydrangea flowers mellow to a rosy pink shade

 

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