Read all about it

Read all about it Calling all garden-minded bookworms!

It's still too early to dig into the garden, but not too early for another rite of spring -- the annual open house at Terrace Horticultural Books. This St. Paul shop specializing in books about plants and gardening will open its doors to the public Saturday, offering a 20 percent discount on all merchandise and a midday guest appearance by local botanist Welby Smith. Smith will sign copies and discuss his new book, "Trees and Shrubs of Minnesota," a 700-page illustrated guide to the state's native and natural trees, shrubs and woody vines. Open house 9 a.m. to 5 p.m.; Smith appearance at 1 p.m. 503 St. Clair Av., St. Paul, 651-222-5536, www.terracehorticulturalbooks.com.

KIM PALMER

New twist on Endless Summer Five years ago, a hot new hydrangea took the garden world by storm. Now its sister plant is making its debut.

Twist-n-Shout is the latest hardy repeat bloomer to appear under Bailey Nurseries' Endless Summer brand. The first Endless Summer, introduced in 2004, was a horticultural rock star, generating headlines, big sales and even an appearance on "Good Morning America."

That massively successful launch rewrote the playbook for plant marketing. Now, much in the way that Coke rolls out new variations, such as Coca-Cola With Lime, to keep fizz in its brand, Bailey is building on initial buzz, adding new hydrangeas to the Endless Summer collection.

The first Endless Summer (think Classic Coke) is now called the Original. A second Endless Summer hydrangea, Blushing Bride, hit plant aisles in 2006. This year brings Twist-n-Shout in the now-familiar periwinkle blue pot.

"The main difference is the flower form," said Bailey spokeswoman Peggy Anne Montgomery. The Original is a "mophead" hydrangea, with a large round bloom that looks like a pom-pom. Twist-n-Shout is a "lacecap," with a flatter, round flowerhead that evokes a lacy cap.

Both are hardy to USDA Zone 4, were developed by hydrangea expert Michael Dirr and have similar coloration, blooming pink in alkaline soil and blue in acidic soil. But Twist-n-Shout has a little more variegation; the smaller (fertile) blossoms turn periwinkle in acidic soil, while the larger (sterile) blossoms remain pink. And Twist-n-Shout has more late-season flash, boasting red stems and burgundy leaves in the fall, thanks to Lady in Red, one of its parent plants. (Penny Mac is the other parent.)

If you want help coaxing your hydrangeas across the color spectrum, Bailey is also offering two new color-changing products this spring. Color Me Pink features pelletized Garden Lime, while Color Me Blue is pelletized Soil Sulfur. Both come with directions and a premeasured scoop.

KIM PALMER

The flower show goes up After a two-year stint on the first floor of the downtown Macy's store, the annual Flower Show is heading back up to the 8th floor auditorium, where it opens Sunday. The theme for this year's popular rite of spring is "We Dream in Color," and is being touted as an around-the-world floral tour from Greece (with a sea of blue hyacinth and blue hydrangeas) to the tropical gardens of South America to the tall cypress of Italy.

If you can't get to the show, don't worry. We'll visit for you and publish a collection of color photos here next week.

The only thing we can't reproduce: That sweet, sweet smell that comes from an auditorium packed with fresh flowers.