by Connie Oswald Stofko
It’s time to start thinking about adding color to your summer garden with tropical annuals, said Ethan Waterman, manager of Waterman’s Greenhouse, 12317 Vaughn St. (Route 240), East Concord (Springville).
While you can buy them now, it’s still too early to plant them outside because they need to be protected from the cold, Waterman said. You want to wait until the air temperatures, day and night, are above 55 or 60 degrees Fahrenheit. If you purchase them now, you can keep these plants in their pots and set them outside when the weather is nice, then bring them back in the house if the day or night is too cool. And you definitely want to protect them from freezing.
With all of the annuals we’re talking about today, some people have great luck bringing them inside at the end of summer and overwintering them, he said.
Mandevilla and diplodenia
Mandevilla and diplodenia are two annuals that are similar to each other, Waterman said. They both love hot, sunny areas and are easy to grow.
The mandevilla has larger leaves and can be used in partial shade as well. The diplodenia is a more compact plant.
Both are good climbers. They can be used in hanging baskets with the plant cascading over the side or trained to grow up a shepherd’s hook. Waterman’s also sells them in pots with trellises, and you can continue to grow them in the container at home. You can also plant them in the ground.
Hummingbirds love the trumpet-shaped flowers.
Waterman’s has mandevilla in pink and white and carries diplodenia in pink and red.
Annual hibiscus
The annual hibiscus is a shrub-type plant.
Whatever size it is when you buy it, that’s pretty much the size it will be. It’s not hardy for our area, and since it will have a short time to grow, it may get only a couple of inches taller by the end of the season, Waterman explained.
It’s also a sun lover. It has multiple flowers on the plant at one time, which provides continuous flowering, but each flower lasts only one day.
Waterman’s carries varieties with flowers that are red, yellow or bi-colored.
Perennial hibiscus
Don’t confuse the annual hibiscus with the perennial hibiscus. Unlike the annual hibiscus, it will grow from the ground up the next year, Waterman said.
It’s a large plant that can get five feet tall. You should cut it back to about six inches or a foot above the ground. Some people suggest doing it in the spring and others say to do it in the fall.
There’s a significant difference in the look of the plant and the shape of the leaves, but if you’re not sure what you’re buying, ask whether the plant is hardy or if it’s an annual.
Perrenial hibiscus benefits from regular spraying to avoid Japanese beetle damage. 1 gallon of hot water, with 1TBL of neem oil, and 1 TBL of castile soap in a big sprayer, shaken to disperse the oil. In addition to spraying after every rain storm (often this season, no doubt), we have dumped out the extra in the sprayer at the base of the hibiscus as a “douse” to improve immunity. Our reward was double the number of blooms, no holes in the leaves, and a happy plant.