Basic gardening myths dispelled

With so many garden myths floating around out there – and just as many helpful gardeners (myself included) passing them along – I was excited at the chance to bust some myths with Jeff Gillman and Meleah Maynard's book, "Decoding Gardening Advice: The Science Behind the 100 Most Common Recommendations." Gillman is an associate professor of horticulture at the University of Minnesota, and Maynard is a master gardener.

Here are some of the basic gardening myths that really resonated with me, and you can find even more in the book.

Myth: Don't plant flowers under trees.

Fact: Flower beds actually can help keep trees healthy. They are also more sustainable than grass in the long run because they require less water. Choose perennials to minimize soil disturbance, and choose the smallest plants possible for the same reason. Carefully work them into the soil that's there, rather than adding dirt for planting.

Myth: Ladybugs are the best predators to release in the garden.

Fact: I never even realized people did this! Ladybugs feed on vegetable-eating insects like aphids and mites. The problem is, they're predisposed to spread themselves out rather than congregate in a single spot. Gillman and Maynard recommend trying other predatory insects, such as the minute pirate bug (Orius species), the big-eyed bug (Geocoris species) and green lacewing larvae (Chrysoperla rufilabris). Buy from a reputable source and release near the insects you'd like them to feed on.

Myth: Full-sun plants grow only in full sun.

Fact: Ask six gardeners to define full sun and you might get six different answers. Jeff and Meleah define it as at least six hours of unfiltered sun between 9 a.m. and 5 p.m., but recommend that gardeners experiment with inexpensive plants to see if they can push the boundaries.

Myth: Divided shrubs will always come back.

Fact: I thought this, too, but it turns out these woody plants have woody root systems that aren't as resilient as other perennials. If a divided shrub survives, it will never develop a natural-looking shape because of its limited ability to regenerate. Shrubs that produce offshoots, like lilacs or spireas, have better odds, but overall, the best way to propagate is from cuttings.

Myth: Divide and transplant only in spring and autumn.

Fact: Most perennials do best when divided in early spring, as new growth begins to emerge. And in spring and early autumn, you don't have to fuss over them much. But experienced gardeners and professional landscapers move, divide and plant when the need strikes, be it spring, autumn or a summer day in between. Protect transplants from hot summer sun and heat by working in the early morning or evening, or on cloudy days. Water well, and if the plants seem stressed, provide light shade until they adjust. Stop transplanting about six weeks before the ground freezes, or you may lose plants to the cold.

Myth: Change potting soil in containers every season.

Fact: Gillman and Maynard agree with a growing consensus that discarding potting soil each year is probably overkill for most container plants. A valid and affordable alternative is to simply work in a little compost from year to year to improve the soil structure and provide added nutrients. But if you're growing a rare or cherished plant you'd hate to lose to disease, it's worth the investment to change the potting soil annually.

West writes for Birds & Blooms and this is from a longer article. Find the full piece and more tips at http://www.birdsandblooms.com.