Sinclair Adam stops before a pet plant and explains its merits to a coterie of horticulturists. Photo by Stephen Wagner

by Stephen Wagner

The temperatures were in the 90s as Sinclair Adam guided us through his trial gardens at Penn State’s Southeast Research station in Lancaster County, a mecca for gardeners, horticulturists and greenhousers.

The usual suspects were present. “Mainly Selecta, Ball, the big contributors in the container program,” Adam said. “Dummen has some entries this year, but we don’t have as many containers from Syngenta as we’ve had in the past … We never know how many items we’ll wind up with in what category. Last year we had 80 geraniums. This year we have about 40. We don’t tell people what to send us. We ask them to enter and we give them a form so they can make choices as to how they’re going to enter the plants … Where we have combinations of three of one species, or one group of plants, they typically perform better than the combinations that are a verbena, a petunia and a calibrachoa, for example.” That is a trend that has shifted over the past four years.

Coleus this season is lush, sturdy, hardy and beautiful in its seemingly endless variety. “New stuff with some very interesting foliage. We have a new dwarf one from Ball, the Spitfire, very compact compared to its kith and kin,” noted Adam. “We will probably prune the coleus back a little bit at the end of July and the beginning of August, otherwise they’ll be this tall [shoulder high], blowing over every time they have the opportunity.” There were some interesting ones assembled by individual plants, per instructions from Benary. “All we’re seeing is the begonia but there is a fuchsia in there,” Adam said, catching the plant hiding. “We do test plants in sun and shade. That’s what the company wants us to do. That’s frequently the case with impatiens, begonia and coleus.”

Why does the dahlia contingent seem to be under par? “You can see down here, the last seven dahlias are not blooming or not growing as vigorously as the others. Why? They came here late. They showed up a week after we’d potted everything else … Some from Danzinger in Israel. Most of their stuff is very, very heat tolerant, and does very well for us. It gets pretty hot out here. We have container temperatures hitting 140º on a sunny day … The temps in and out are pretty hot. These dahlias look pretty good; they were deadheaded two weeks ago.”

Scattered about, but not at random, are plants with a blue flag. That means they got a superior rating on the first rating, which was done July 2 – 7. “It takes me about 24 hours to do a rating” or about two minutes per plant, Adam said. He notes the rating on an iPad and “immediately that’s loaded onto our web page.” Ratings are posted from 2017 to today. Pink flags? “That’s where my interns can collect leachate data. Every week we test pH and EC doing pour-through measurements.”

Adam mentioned the snapdragons. “I’m a big snapdragon fan. These come to us from American Takii … Good plants, really nice habit, no rust. That’s typical of the smaller varieties of snapdragons.”

One reason for interspacing varieties is that it is basically a pathological protocol. “We’ll put one company’s geraniums down, and then a spacer crop, and then another company’s geraniums so that no two geranium entries from different companies are adjacent. That way, if there’s any Xanthomonas this is one way we can be secure. Incidentally, we haven’t seen that since I’ve been here,” Adam said.

“Welcome to Petunia Central: 119 petunias this year – quite an array,” he announced. “The usual players brought some new things. This is from Ball, color rust, yellow, something they’ve been working on. Ball and Selecta were the first two plants to show up this year for planting. The color-rust theory is a really good one, I think. Strong colors. The best-selling petunia in Lancaster County is still Supertunia Vista Bubblegum from Proven Winners.” One attendee wanted to know what Adam would recommend as a suitable substitute for Supertunia Bubblegum. “ColorRush Pink is pretty good. It’s a little different hue, not as orangey-pink. It’s more of a blue-pink so there’s a little subtle difference in the view but it’s a real good performer, but not quite as large in habit.”

A flower that Adam said he’s enjoyed for years is Evening Sensation, “which does have a fragrance – a little more pronounced at the end of the day but a very strong grower that has a lovely petunia fragrance to it. If you’d have been here three days ago before the massive rainstorm these were a lot more floriferous.”