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Digging It Up
Alyssum “Snow Princess” as it appeared in the Trial & Idea Garden in July 2010 — a great performer even in hot and dry summer conditions.

This week, I have a guest columnist.

Pat McCallum of Carlisle, a Penn State Master Gardener, evaluates plants being trialed at the Master Gardeners' Trial & Idea Garden, which is at the corner of Claremont Road and Army Heritage Drive, on the grounds of Claremont Nursing & Rehabilitation Center.

At the end of the season, Pat writes a review of the winners and the not-so-winners.

With a hard frost and the outdoor gardening season finally drawing to a close, now is a good time to reflect on the past season and to plan for bigger and better plants next year.

To that end, here is Pat's report on Trial & Idea Garden varieties of 2010:

"Wow" ... or ... best kept "Out of Sight." There were plants at both ends of the spectrum in this year's Trial & Idea Garden.

Almost perfect. That is the final assessment for Alyssum "Snow Princess," which topped the plant ratings this year and would have received a perfect score if not for the lack of uniformity in plant size during the first month after it was planted.

After that erratic start it took off, forming plants with hundreds of small white flowers that became great ground covers at just a foot high or even better filler plants, each growing to about 30-inches wide.

Each plant loved the sun, tolerated the heat and fully covered at least four square feet of ground.

The biggest surprise was the runner-up - Rudbeckia hirta "Tiger Eye Gold." No other rudbeckia has ever been honored in the trials, but this variety, unlike all the others, maintained an attractive appearance all season with its great looking flowering clumps of many blooms and no disease.

This is a short plant with great impact, standing only about a foot high, perhaps 16-inches wide, with about 50 three-inch flowers per plant.

Scoring equally as high were the SunPatiens trio of "Compact" varieties in lilac, white and blush pink. Here are plants that thrive in the sun while resembling the look of New Guinea Impatiens with their large blooms and dark glossy leaves.

Their almost look-alike rival, Vinca "Cora Deep Lavender," a more traditional selection for sunny locations, performed almost as well.

Two especially good border plants were Alyssum "Clear Crystal Purple Shades" and Marigold "Yellow Gem." This alyssum, while reaching only half the height and width of "Snow Princess," proved to be almost as stellar a performer but more suitable for smaller spaces.

The marigold featured hundreds of half-inch flowers on plants 18-inches high and three-feet wide and looked fine until mid-August, when it started to get leggy. It might profit from a mid-season trimming.

Its sister plant, Marigold "Red Gem," performed similarly but showed slightly more decline - legginess, dead areas, loss of center - as the season progressed.

At the bottom of the ratings were the nasturtiums. Overall, they formed sizeable clumps, but the leaves grew so robustly that they hid the very few flowers that bloomed while curling and yellowing in the heat and otherwise demanding attention.

Several plants were especially disappointing. Cosmos "Limara Lemon" appeared to be a great alternative to marigolds or coreopsis in June but declined quickly beginning in July, sustaining insect damage and death as the season wore on.

Plants that did live, but not up to expectations, were Petunia "Pretty Much Picasso," Cordyline australis "Southern Splendour," and Salvia "Black and Blue." The petunia and its relatively small, almost tubular flowers and sclerotic leaves sprawled.

The cordyline, a pretty pink and green specimen, proved to be a timid, reluctant grower; it may be suitable for use in a small space that requires controlled growth.

The 32-inch tall sun-loving salvia was very healthy but stingy with its flowers, putting on a noticeable show only for a short time.

This year, for the first time, the Trial & Idea Garden included vegetables and herbs. Both the basil ("Genovese" and "Nufar") and the dill ("Dukat") grew well.

Pinching off flower heads on the basil encouraged leaf growth, and leaving the 10-inch flower heads untouched on the dill produced a bountiful seed harvest.

No one really knows how many tomatoes were produced by the "Big Beef," "Big Boy," and "Brandywine" tomato plants because they loved where they were planted more than anyone anticipated. They simply got so big no one could see into the middle of the plants.

All produced abundantly, but the "Brandywine" probably produced the largest, with at least one tomato weighing in at one pound four ounces.

Most abundant on the eggplants were the flea beetles, which ravaged the leaves to almost nothingness. Nevertheless, the eggplant "Gretel" managed to yield a couple dozen five-inch long cream-colored eggplants, but "Satin Beauty" produced few, albeit beautiful, purple fruit.

"Gretel" is reportedly often grown as a container plant, but you probably won't want it on your patio unless you are willing to control the flea beetles.

Thank you, Pat ... now we know what to add to our wish list for 2011.

Annette MaCoy is the extension educator for consumer horticulture and the Master Gardener coordinator at Penn State Cooperative Extension, Cumberland County. She can be reached at 240-6500 or