Annuals you’ll want to plant next spring
It’s time for our end-ofyear review of the annuals grown at the North Park Demonstration Garden.
The garden is planted and maintained by Penn State Extension Master Gardeners of Allegheny County. It is a satellite of the Penn State Flower Trials at the Southeast Agricultural and Research Center in Manheim, Pa. The information gleaned from plant evaluations is put to use by breeders, growers and nursery professionals in selecting plants they’ll offer in 2023.
For local gardeners, it’s a chance to see how plants purchased in market packs or small pots in the spring will fare in their gardens. Online and catalog sources for seed can also be crosschecked with many cultivars that were trialed locally or at the main trial site. The flower trials website at agsci.psu.edu is especially useful with ratings for plants posted at intervals through the growing season.
Plants at the demonstration garden are sprayed to deter deer. Fertilizer is applied throughout the season. For your own garden, annuals benefit from a slow-release fertilizer applied at planting time. Another option is to use a balanced water-soluble fertilizer every few weeks.
Note that petunias and million bells (Calibrachoa) are “heavy feeders” that prefer slightly acidic soil. They will thrive best with an occasional boost of fertilizer formulated for their needs once the heat of late summer arrives. Plants grown in containers will also require more frequent feeding as nutrients are reduced in peatbased mixes versus garden soil.
At the North Park location 11 plants scored a perfect 5. Seven of the top performers were petunias including: “SureShot” White and Blueberries & Cream, “DuraBloom Electric Lilac,” “Main Stage White 22,” “ColorRush
Pink Vein,” “Fun House Amethyst Sunshine” and “Itsy Magenta.” Several of these petunias feature smaller blooms, but are very prolific. Many new petunia cultivars are “self-cleaning,” meaning that they do not require frequent removal of spent flowers to maintain a pretty show.
The remaining annuals rated at 5 in our region include:
• BIG “Deep Rose Bronze Leaf” begonia is a good option for shade gardens, but performed well in our sunny display gardens, too.
• “Bright Sparks Burgundy” celosia is a superior bedding plant reaching 2 feet tall and equally wide. It has fluffy, long-lasting plumes and makes a great exclamation point in the garden.
• “Zydeco Cherry” zinnia is a fully double flowered zinnia. It’s 3½-inch wide flowers attract pollinators and are good cut for the vase.
• “Labella Maggiore Deep Rose” dahlia is a bushy 26inch tall and wide plant that is propagated from cuttings and will be found in small pots at local nurseries next spring.
We poll visitors at our August Garden in the Parks event. This year the favorite plant was “Lascar Purple + White” verbena with its warm purple bicolor flowers. Plants have a mounded habit and reach 20 inches tall and wide in our trial gardens.
Master Gardeners’ top choice was “Graffiti 20/20 Appleblossom” pentas. It sports clusters of starry flowers in shades of pale to deep pink. It reaches a height of 30 inches and is suitable for containers and as a bedding plant.
Visitors and Master Gardeners were unanimous in selecting “SunStanding Jazzy Coral” New Guinea impatiens as a favorite. Its soft yellow leaves are edged in deep green, setting off rich coral flowers. Thirty-inchtall upright plants will glow in both sunny or shady spots.
Another top choice for both groups was “Granvia Gold” strawflower ( Bracteantha spp.), which makes its appearance at the top of the list for the second consecutive season. Like most strawflowers, “Granvia Gold” is heat- and droughttolerant. Vigorous and disease-resistant, its bright yellow flowers are continually produced on sturdy 28inch tall and 30-inch-wide plants.
The plants described are just a sampling of the myriad options that will be available to gardeners for 2023. If you’ve been choosing the same palette of annuals for your garden year after year, now is the time to consider some fresh options. Penn State has done the research on plants that won’t disappoint! Carol Papas is a Penn State Master Gardener, a volunteer program that supports the outreach mission of Penn State Extension. Extension provides research-based information on best practices in sustainable horticulture and environmental stewardship. For more information, contact the Penn State Extension of Allegheny County at alleghenymg@psu.edu or 412-482-3476.