Your lawn or backyard growth plans might not be as ambitious as Versailles' manicured grounds, but a good garden center has the inside info on the plants and plans that will make your outdoor space thrive. Top-notch centers employ in-the-know staffers who can tell you what to plant where in addition to selling quality annuals and perennials. And in many cases they'll offer good prices, too. But some garden centers have overpriced, droopy flowers and even droopier employees.

As warmer weather sets in, gardens and landscaping move up on our to-do lists. Even the greenest of thumbs sometimes needs help — sometimes lots of it. Which plants to buy? How to plant them? Where to plant them? How to nurture them?

The best-run garden centers have the answers. Running a good garden center or nursery takes knowledge, years of experience, organizational skill, and a strong commitment to quality. And since most garden centers buy — rather than raise — most of what they sell, buying ability and buying standards vary.

If you need help, nonprofit Twin Cities Consumers' Checkbook's ratings of area garden centers for quality and price can help you find it. Until May 5, Checkbook is offering free access to its ratings of area garden centers to Star Tribune readers via

The opinions Checkbook collected from local consumers on garden centers they use reflect the big variation in quality among retailers. Some stores were rated "superior" overall by at least 80% of their surveyed customers, but several other retailers were rated "superior" by 30% or fewer.

For the selection of plants they sell, Home Depot and Menards did very well on price. Menards' prices averaged 46% below the all-store average for comparable items, and Home Depot's averaged 34% below the all-store average. Unfortunately, both received well-below-average ratings on "quality of products." Although none of Lowe's stores received 10 or more ratings in our surveys of consumers, the threshold for being included in the ratings, we found it also offers very low prices.

Unlike most types of services and stores Checkbook evaluates, paying more for plants at garden centers does slightly improve your odds of getting better advice, service and product quality. Checkbook found that many of the stores rated highest for quality charge higher-than-average prices, but some stores that rate high for quality also have below-average prices.

For specific plants, Checkbook's undercover shoppers found enormous nursery-to-nursery price differences. For example, for a lavender in a 6-inch pot, prices ranged from $2.99 to $24.99; and for a sansevieria in an 8-inch pot, prices ranged from $15.99 to $59.99.

Before shopping, make a plan. Consider your yard's soil type, acidity, drainage patterns and sunlight exposure, and match plant types with areas where they are likely to thrive. Your plan should show how your property will look right away, and how it will look years from now when your plants have grown. Without a plan, you could wind up with an assortment of plants that do not complement each other in size, shape or color. You might end up with shade where you want sun and with the view from, or of, your house obscured.

Seek advice from gardening websites, friends with attractive gardens and experts at local botanical gardens. If you want professional help, you can hire a landscape designer.

When making plant purchases:

• Check roots to be sure they have not dried out. Probe with your finger or look through the drain holes of a container to make sure the roots are whitish, not brown.

• For shrubs and trees, check for weak or broken branches. Bark should not have scars or holes.

• Check plants for browned or grayed areas or spots on leaves or stems, all signs of disease. And check for insects.

• In growing season, be sure there is new growth.

• Get a receipt that shows the common and the Latin names of plants and the size, number purchased, date of purchase, price and guarantee.

• Ask what guarantee you get. Fortunately, even though many plant deaths are the result of improper planting or care — in other words, the buyer's fault — most garden centers nonetheless offer broad guarantees.

Twin Cities Consumers' Checkbook magazine and is a nonprofit organization with a mission to help consumers get the best service and lowest prices. We are supported by consumers and take no money from the service providers we evaluate.