George's Current Ramblings and Readlings

What the New USDA Hardiness Zone Map Means for Gardeners

February 13th, 2024

   If you pay attention to which plants tend to croak in our winters – and as a gardener, you should – you’ve probably noticed less cold-weather mayhem over the past 20 years or so.

USDA came out with this newly revised Plant Hardiness Zone Map late last fall.

   Although our temperatures can nosedive to zero or below, that’s been happening less and less. And as a result, our odds have been growing that we can get away with plants that not too long ago were considered “iffy” at best in our climate.

   The U.S. Department of Agriculture has now verified what gardeners have been suspecting for years – our winters generally aren’t as plant-killing cold as they used to be.

   USDA late last fall released an updated version of its Plant Hardiness Zone Map – the official, national guide that gardeners and farmers use to estimate how low temperatures are likely to plunge in an average winter.

   These zones are listed routinely on plant tags and are a key determiner of what plants gardeners plant in a given area and which ones garden centers carry in the first place.

   The new map is based on 30 recent years of nationwide observations – from 1991 to 2020 – that show our winter lows are about two degrees warmer, on average, than the decades before.

   USDA last updated the map in 2012, using temperature readings from 1976 through 2005.

   The readings went up enough over the more recent period to cause USDA to shift about half of the country – Pennsylvania included – into higher half-zones.

The Best New Trees and Shrubs of 2024

January 30th, 2024

   A hydrangea with dark leaves, a mock orange that reblooms, and an inkberry holly that solves the “bare-legs” problem are among the most interesting new trees and shrubs hitting the market for the 2024 growing season.

Eclipse is a mophead hydrangea that combines dark foliage with cranberry-colored flowers.
Credit: Bailey Nurseries

   Growers, local garden centers, and other plant experts mentioned the following 12 choices for my annual January four-part, best-new-plants series.

   Today’s new trees and shrubs make up the final installment of this year’s series.

   Part one on best new edibles of 2024 appeared on Jan. 9, part two on best new annual flowers of 2024 appeared on Jan. 16, and part three on best new perennial flowers of 2024 posted last Tuesday, Jan. 23.

   Some of the following new tree and shrub varieties are available online and in some plant catalogs. Most also will be available in local garden centers beginning in April.

   The details:

Hydrangea Eclipse

   This new bigleaf hydrangea in Bailey Nurseries’ First Editions line is being touted as the “first true dark-leaf mophead hydrangea.”

   Ryan McEnaney, “Field Guide to Outside Style” author and Bailey communications manager, calls Eclipse an “impressive bloomer and solid garden performer.” But he says what really sets the variety apart is it “has such dramatic and different foliage than any other hydrangea out there. It gives you the opportunity to do something different with one of the most sought-after plants in the world.”

   McEnaney adds that the dark-purple leaves hold their color even in warm weather and pair nicely with the ball-shaped, dark-purple to cranberry-colored blooms.

   Eclipse turned enough heads at last summer’s AmericanHort Cultivate show that it won a Retailers’ Choice award as a new plant with the potential to become a garden-center best-seller.

   It also won the 2024 National Garden Bureau Professional Choice Green Thumb Award as the year’s top new shrub.

   Plants grow three to five feet tall and wide, ideally in morning sun and dappled afternoon shade.

Could Worry Free Ruby Snow be the best panicle-type hydrangea yet?
Courtesy of Overdevest Nurseries

Hydrangea WorryFree Ruby Snow

   Lots of superb new panicle hydrangeas have come along in the last 10 years to make this species one of our showiest and easiest-to-grow summer-blooming shrubs. So it takes a lot for yet one more newcomer to make a noticeable dent in an already-impressive field.

   Lower Paxton Twp. horticulturist David Wilson, marketing director for Overdevest Nurseries, believes Ruby Snow manages to do that with its huge, sturdy, long-lasting, color-changing flowers that end up in a deep ruby-red color even past frost.

   Wilson says the over-sized, cone-shaped flowers start out “gleaming white” in early summer, then take on a soft-pink color, and then intensify into a bicolor bright pink with white tips before morphing into ruby-red by late summer into fall.

   “It flowers all over the plant, and it has a tremendously long seasonal display,” Wilson says. “We’ve been testing it for five years and planted it out to compare it with all the major hydrangea panicle introductions. I have come to the conclusion that this is the best panicle selection I have ever seen.”

   Besides the flower performance, Wilson adds that the sturdy stems hold the big flowers upright. “It doesn’t flop like many old-fashioned varieties that hang their heads,” he says.

   Ruby Snow grows a compact four feet tall and five feet wide and does well in full sun to part shade.

The Best New Perennial Flowers of 2024

January 23rd, 2024

   A cross between coneflowers and gloriosa daisies, a new variety of a little-known native plant, and the smallest native Joe Pye flower yet top the list of interesting new perennials debuting in the 2024 growing season.

Echibeckias are a cross between coneflowers and rudbeckia.
Credit: Quality Greenhouses

   Growers, local garden centers, and other plant experts picked the following 14 choices for my annual January four-part, best-new-plants series.

   The article on best new edibles of 2024 appeared Jan. 9, while the rundown on best new annual flowers posted last Tuesday, Jan. 16. The series ends next Tuesday, Jan. 30, with a look at the best new trees and shrubs of 2024.

   The following new perennial flowers are available online and in some plant catalogs and will start showing up in local garden centers in April.

   The details:

Echibeckia Summerina series

   You probably have never heard of an “echibeckia,” which is understandable since the plant is a recently developed cross between coneflowers (Echinacea) and gloriosa daisy (Rudbeckia). But if you lean toward the new and different and are willing to accept the possibility that this “perennial” may not make it through our winters, consider that the Summerina series of echibeckias was showy enough to earn the 2023 Editor’s Choice Medal of Excellence award from the Greenhouse Grower trade magazine.

   The producer of this 10-color series, California-based Pacific Plug and Liner, touts the line as the “most interesting plant in the world” for the big flowers, fast growth, long bloom time, disease-resistance, and flower colors that offer “bursts of rich browns, oranges and yellows.”

   The plants have the habit and central flower cones of coneflowers but the warm colors of gloriosa daisies.

   The down side is that these hybrids are listed as winter-hardy only down to Zone 7, which puts them in the border-line “safe” zone for most of the Harrisburg area, which is now listed as Zone 7a in the newly revised U.S. Department of Agriculture Winter Hardiness Zone Map.

   Echibeckia prefer full sun and overwinter best in a protected microclimate, such as along a heated house wall.

Stokesia Totally Stoked ‘Riptide’ is a pollinator-friendly native perennial that’s not well known.
Credit: Proven Winners

Stoke’s aster Totally Stoked ‘Riptide’

   Stoke’s aster (Stokesia laevis) is another little known perennial despite being a U.S. native wildflower.

   Robert Kadas, owner of Highland Gardens in Lower Allen Twp., thinks a new variety of it called ‘Riptide’ has the potential to become a hit, given the recent popularity of both native plants and ones that are pollinator-friendly.

   “I’ve always loved stokesias because of how easy they are to grow for most people,” Kadas says. “’Riptide’ has abundant periwinkle-blue flowers through the summer on rich, dark-green foliage. It’ll form a nice, dense plant that grows two feet tall and three feet across.”

   He adds that this is a perennial that tolerates heat and humidity well, is loved by bees and butterflies, and is hardly ever bothered by deer or rabbits.

   Proven Winners is introducing ‘Riptide’ as one of the first two entries in a new series called Totally Stoked. The other newbie is a white-bloomer called ‘Whitecaps.’

The Best New Annual Flowers of 2024

January 16th, 2024

   A super-cold-hardy dusty miller, a double-award-winning purple-blooming agapanthus, and a whole new type of succulent are among a slew of interesting new annual flowers debuting in the 2024 growing season.

Semponium ‘Diamond’ is one of the entries in a whole new type of plant called Surrreal semponiums.
Credit: Monrovia

   Growers, local garden centers, and other plant experts picked those and more for my four-part, best-new-plants series that I compile each January – a good month for gardeners to plan what to plant in the coming season.

   The article on best new edibles of 2024 appeared last Tuesday, Jan. 9. The best new perennial flowers of 2024 will post next Tuesday, Jan. 23, and the best new trees and shrubs of 2024 is scheduled for Jan. 30.

   Some of the following 14 new annual flowers are available in seeds or plants online and in some plant catalogs. Most also will show up in plant form in local garden centers beginning in late April to early May.

   The details:

Surreal semponiums

   What do you get when you cross a cold-hardy hens-and-chicks plant (Sempervivum) with a tender Aeonium?

   British breeder Daniel Michael managed to do just that and came up with a new cross called “semponium” that offers a range of interesting leaf colors and formations.

   Succulent fans and those looking to try anything new and different will love this new five-variety series named Surreal, which is debuting in the U.S. this spring.

   Semponiums blend the glossy, colorful leaves of Aeonium with the rosette habit and equally colorful leaves of hens-and-chicks.

   “They are amazing, huge, colorful succulents that are more hardy than traditional Aeonium,” says Monrovia plant selections manager Georgia Clay, who rates Surreal semponiums as her favorite new annuals of 2024.

   Although semponiums are cold-hardier than Aeonium (which are grown as houseplants or annual pot plants in Pennsylvania), they’re not as cold-tough as hens-and-chicks (perennials in Pennsylvania). They’ll be sold as Zone 8 annuals and can be over-wintered here inside as houseplants.

   The five varieties include ‘Sienna’ (14 to 16 inches tall with red leaves), ‘Vortex’ (10 to 12 inches tall with a spiraled rosette of dark outer leaves and neon-green centers), ‘Destiny’ (16 to 18 inches tall with reddish-black leaves), ‘Diamond’ (10 to 12 inches tall with bright green leaves that have red edges), and ‘Mrs. Frosty’ (10 to 12 inches tall with narrower brownish-pink leaves).

   Plants are deer resistant, grow in full sun to part shade, and like most succulents, don’t need a lot of water.

Agapanthus Blackjack has unusual dark-purple flowers.
Credit: Concept Plants

Agapanthus Black Jack

   A plant that earned 2023 Plant of the Year honors at last year’s Chelsea Flower Show in London – and a People’s Choice award in 2024 National Garden Bureau Green Thumb voting – is another interesting British import coming to U.S. gardens this spring.

   Agapanthus Black Jack is a strappy-leafed plant that produces striking lily-like dark purple flowers atop sturdy stems.

   In the South, agapanthus is a durable, evergreen, drought-tough plant that comes back year after year. It’ll be sold as a perennial as part of the Southern Living Plant Collection in Zones 8 and up.

   In Pennsylvania, Black Jack is better suited as a summer-flowering pot centerpiece that can be overwintered dormant in an unheated garage or basement.

   What’s unusual about this agapanthus is that the flowers are so dark purple that they open from black buds and border on black at first – different from the more common blue or white shades of agapanthus (sometimes known as African lily or lily-of-the-Nile).

   Black Jack grows about 20 inches tall, does best in part sun, and is deer resistant. Note that agapanthus is toxic to humans and pets if eaten.

The Best New Vegetables and Fruits of 2024

January 9th, 2024

   A lot of winter is still staring us in the face, but for gardeners, it’s a time to dream about the many plants already awakening in greenhouses.

Fruit Snacks apple trees are narrow but heavy-yielding.
Credit: Plants Nouveau

   Some of these plants will be new to the market in 2024 – improvements or new twists that haven’t been grown in home gardens yet.

   To help you decide which of the newcomers to consider for your 2024 gardens, I’ve scoured the trade and asked numerous experts for what they believe are the best of the best plants making their debut.

   Let’s zero in today on 10 of the year’s best new vegetables and fruits.

   Next week (Jan. 16), we’ll take a look at the best new annual flowers of 2024, then on Jan. 23 we’ll cover the year’s best new perennial flower introductions. The series concludes Jan. 30 with a look at the year’s best new trees and shrubs.

   Some of the following new edibles are already available online and in catalogs. If any strike your fancy, it’s best to order ASAP before the supply dwindles.

   Others will show up in local garden centers – seed packets already and plants in April and May.

Fruit Snacks apple trees

   Four dwarf, columnar apple trees are the first in this new-for-2024 line of Fruit Snacks fruit plants with the tag line, “Real fruits you can reach and eat.”

   Angela Treadwell-Palmer, co-owner of the Plants Nouveau company that’s debuting Fruit Snacks, says the line comes in response to recent home-gardener demand for compact tree fruits that are easy to grow.

   “These perfectly upright, dwarf and skinny apple trees make it easier to pick delicious snacks,” she says. “Fruit Snacks are perfect for small spaces. They make lovely hedges and will grow perfectly in pots.”

   The four new varieties grow eight to 12 feet tall but only about three feet across. Full-sun locations are best, and two different trees are needed to cross-pollinate and produce fruits.

   The varieties also were selected for their resistance to scab and rust – the two main maladies of apple trees.

   Debuting in 2024 are: Blushing Delight (green-gold fruits with a red blush); Golden Treat (a slightly tart variety with golden fruits); Tangy Green (a tart, green variety similar to Granny Smith), and Tasty Red (a slightly tart red-fruited variety).

Kitchen Minis

   This line of super-small, pot-grown tomatoes, peppers, and cucumbers also comes with a tag line: “No garden? No problem.”

Cucumber ‘Quick Snack’ is the newest introduction in the Kitchen Minis line.
Credit: PanAmerican Seed

   Ashcombe Farm and Greenhouses in Monroe Twp. plans to carry two varieties of starter-size Kitchen Mini plants in early spring: a foot-tall, red-cherry-type tomato called ‘Siam’ and a new-for-2024 compact, self-pollinating cucumber called ‘Quick Snack.’

   “These are meant for indoor kitchen-window growing,” says Ashcombe co-owner Kerri Laudig. “The plants produce small, snack-size fruits that are perfect for a small family in early spring before the gardening season begins. They’re novel and home-grown fun.”

   The potted plants can be moved outside on a patio or table top after frost so long as they’re still producing.

   ‘Quick Snack’ also is winner of the 2024 National Garden Bureau Green Thumb Award for the year’s best new edible in both the People’s Choice and Professional Choice categories.

   The Kitchen Minis line, produced by Pan American Seed, includes two other compact cherry tomatoes, three mini sweet peppers, and six varieties of miniature hot peppers.