New USDA Plant Hardiness Zone Map

New USDA Plant Hardiness Zone Map.

  

This morning the United States Department of Agriculture (USDA) released a new Plant Hardiness Zone Map, replacing one introduced in 1990. The new map is much more accurate and detailed than all earlier additions and reflects data down to ½-mile scale.  This allows viewers to search to their individual zip code, as well as view state and regional maps, or the entire country.   An on line interactive feature allows users to view details of their specific neighborhood.

Mail order companies and wholesale growers will be able to utilize the links between zones and zip codes. This feature will provide important information to guide the best time to ship tender plants to a specific area of the country.




The 1990 map was in a static format and offered less detail than the new map

To create this map the USDA used new methodology involving a complicated algorithm.  New zone boundaries were determined from the collected data of the lowest minimum average winter temperature from over 8000 reporting stations, along with elevation, the slope of the land, the nearness to water, and prevailing winds.  Where the old map had relatively straight lines, the new map lines are more jagged and more accurately depict the zone of any individual area. 

The map does not reflect the nano spots in an individual garden where both hot and cold spots may cause up to a full zone of variation. Common sense and observation must always prevail: a south facing white wall is going to reflect heat, a thick tree canopy will moderate cold, etc. 

Kim Kaplan of the USDA presented the map during a webinar this morning and fielded questions from the press. Bart Ziegler of the Wall Street Journal and Seth Borenstien from the Associated Press both addressed the question of how the map may demonstrate climate change. The majority of changes made to the map involved warmer vs cooler zones in the northeast region of the U.S. Additionally, of 34 cities mentioned, over half are now listed in a warmer zone. Kaplan was reluctant to associate any connection to climate change and repeatedly stated the USDA does not have evidence showing what caused the changes. She also noted that, while many areas increased a half zone, most represented a minor temperature change with as little as .5°F affecting the change.

Find additional information on the USDA Agricultural Research Station website at http://www.planthardiness.ARS.USDA.gov . Information on how the map was made and other frequently asked questions are addressed and maps of varying resolutions and formats are available for download.

 

Winter Bark and Buds

The trunk of a birch tree brightens a snowy landscape

Cornus sericea 'Baileyi'

I can't think of anything brighter in the winter landscape than the bold red stems of a Red Twig Dogwood, Cornus sericea. Native to many parts of the United States, the red twig passes the summer unnoticed, yet by the time the leaves drop in fall the stems are shockingly red. There are many variations of the species; C. sericea 'Baileyi' has exceptionally red stems, the stems of C. s. 'Flaviramea' take on a deep golden yellow color in the winter, and C. s. 'Midwinter Fire' captures the orange red colors of flame.

A patented variety of Red Twig Photo from Bailey Nursery

While not as bold as the Red Twig, the trunks of many trees offer dramatic winter interest.


Betula and Salal

Birch (Betula) are known for the sharp intensity of its white peeling bark, which monochromatically blends into the landscape after a snowfall. The bark of some maple (Acer griseum) and cherry (Prunus serrula) trees offer a striking contrast against a snowy backdrop, with rich mahogany layers that peel away to revel the cinnamon colored trunk underneath. Even without snow, the trunks of these trees will capture the eye, much like the bark of Arbutus, Lagerstroemia, and Stewartia.
  


Prunus serrula at the
UBC Botanical Garden




Acer griseum a
t Missouri Botanical Garden



Arbutus at
Sunny Oceanview House;
Vancouver, BC

As the months progress, winter yields to the promise of spring; flower buds, often set the previous summer, swell in anticipation. 


showy red buds on Pieris 'Valley Rose'

Pieris is noted for cascading flower clusters in early spring and red color on new leaves. In winter, buds become a showpiece against the attractive evergreen foliage. Pieris 'Little Heath' and P. 'Flaming Silver' offer additional interest with variegated foliage. Additionally, many Rhododendrons have showy buds through the winter months.


Pieris 'Flaming Silver'- variegated foliage AND showy flower buds

And, my favorite for winter bud color is Viburnum tinus 'Spirit'. An abundance of red buds and white flowers share center billing against a backdrop of glossy dark green leaves and red stems. Later reddish-purple berries will accompany the flowers. Spectacular! Young plants are great in fancy deck pots through the holidays.

Viburnum tinus 'Spirit'  - great looking buds, flowers and foliage.

As you drive around – casually observing holiday displays or frantically getting your shopping done - take time to notice the plants around you. You will find many colorful gems to brighten your world.

Next week:  Winter flowers.  




Perfect Gifts for Gardeners

There are an uncountable number of gifts appropriate for the gardeners in your life. Finding the right one doesn't need to be daunting. The following are my personal favorites to guide you on your trek.





Check out this no nonsense cobra-shaped blade!

CobraHead^® Weeder and Cultivator – If I could only have one garden tool, my CobraHead^® Weeder and Cultivator would be it. It is far superior to any individual trowel, cultivator, or weeder I have ever used. For planting, it will dig a hole and easily score pot-bound roots. For cultivating or weeding, the unique design and sharp narrow blade easily lifts shallow rooted plants, as well as cuts into the ground to remove tap-rooted weeds (like dandelions) without disturbing surrounding plants. From prying rocks out of glacial till soil to killing slugs, there are tons of alternate uses for the CobraHead®. Noel Valdes, created the first CobraHead®tool for his own use, and soon decided it was the best tool in earth^®. The family run business embraces organic gardening and a sustainable approach to life while they continue their mission to produce their products locally (vs overseas).

My well-loved Felco pruners and scabbard

PRUNERS: Any exceptionally designed pruner can turn a chore into an enjoyable task. This is how I feel about my Felco pruners. Felco has a comparative chart on their website to help guide a buyer to the proper tool for the intended job. They may seem more expensive than other pruners, but they are strong proof that you get what you pay for. They are made to prune, and made to last. My Felco pruners have been loyal garden companions for over 20 years. ("If I could only have two tools…CobraHead and my Felco #2s!"). A scabbard makes a nice accessory gift; it allows your gardener to carry their pruners anywhere they go.   

Eat Your Yard! by Nan Chase offers great stories and recipes for enjoying ornamental-edible plants

Books cover every type of gardening you can imagine.

BOOKS : Whatever theme you are considering- whatever genera or style- there is undoubtedly a multitude of garden books devoted to the subject. New gardeners will appreciate a book that covers basic skills, design tips and plant information. The Sunset Western Garden Book has been a standard on the west coast for generations. A gardener, who also loves birds, might appreciate a book on landscaping for birds. A world traveler may enjoy re-living a trip to Italy with a book on Italian gardens. And, who doesn't love to eat? If your gardener enjoys growing vegetable or fruits, why not a book on sustainable landscapes. The options are limitless, but if you find yourself overwhelmed, the Center for Urban Horticulture Library maintains fabulous booklists by topic. (note: This library carries over 15,000 titles!).

Reinforced fingers insure these will last season after season

  

GLOVES: Garden gloves have come a long way since the thin cotton gloves of yore – a serious gardener could wear out a pair in a matter of hours. West County Gardener® represents the best of today's glove options. Company founder, Beverly Schor, took her skills in developing performance athletic gear to solve her frustration with conventional garden gloves.West County Gardener® gloves are sturdy enough to tackle any garden task. They are form fitting , washable, breathable, durable, and designed to fit the broader hands of a man or the narrower longer fingered hands of a woman. Lots of great colors too! I have several pairs I use for kayaking, sailing, winter driving, walking the dog, oh yes…and gardening!

So fun...a color for everyone...and a shut off valve!

Dramm makes watering fun with brightly colored, functional watering wands. Made in the USA and designed to last a lifetime, Dramm tools have been an industry standard for almost 70 years. The original nozzle design offered large quantities of water that flowed in a spray gentle enough for new seedlings. They offer several designs to cover all bases. I also like their Revolver™, Spray Gun with nine spray patterns that allow you to switch from watering your new annuals to jet blasting your driveway with a quick twist of a dial.


Vaccinium 'Pink Lemonade' prodcues wonderfully sweet pink blueberries

 PLANTS: Let's not forget…gardeners LOVE plants! Collectors are easy because anything unusual will work. Plants that do double duty in a container are a great option if you are less sure what will work. Moreover, plants new to the market are always fun. One idea that will work for practically anyone is Pink Lemonade Blueberry, a blueberry with pink fruit. Collectors will love it as the first pink blueberry, new gardeners will find it easy to grow, edible gardeners will appreciate its sustainability and kids of all ages will delight in the yummy pink fruit.

PEACE Gnome-a gift from my stepson last year

ART: I like art with dual functionality such as a pretty glass-art hummingbird feeder or wire-art that doubles as a plant stake. Pots and birdbaths come in all shapes and sizes and in a wide variety of materials. Inspiration is as close as your local garden center.

MEMBERSHIPS: American Horticultural Society Membership has many benefits including an every other month magazine, reciprocal admission to botanical gardens and historical sites all across t
he country, a seed exchange, and discounts on educational programs and publications. Plus, it supports horticulture. There are organizations to match any horticultural interest (hostas, rhododendrons, perennials…) so it is easy to match your gardener to an organization they will enjoy

Gifts FROM YOUR GARDEN: If you are a gardener, here is the chance to share your bounty. Take divisions of your favorite Iris, make homemade jams and preserves from your fruit trees, or bake a cobbler from those fresh berries you harvested earlier this summer. Alternatively, how about a homemade gift certificate with the promise to share your tools and elbow grease in a spring cleanup?


A friend of mine once received a truckload of composted manure as a gift. She was thrilled,… I was jealous,…but many others were appalled. Unless you are 100% sure such a practical gift would be well received, you may want to consider alternate ideas to spread

the joy of gardening.

Whether functional or foo-foo, gifts for gardeners show you acknowledge their world of plants. Feel free to share your ideas on the perfect gift …. Maybe I will find something new to add to my list.



Next week: Winter bark and buds. 

Berries for Winter Color

Berries are the jewels of winter – decorating the landscape like ornaments on a Christmas tree. 

As part of my series on winter color, let’s talk berries.  Berries are a fleshy fruit surrounding the seeds of a plant.  They can be borne singly or in clusters.  Edible or solely ornamental, berries may be found shrubs, trees, or groundcovers.  

Here are some of the ones I have in my yard:   

Holly is a traditional symbol of Christmas and probably the first plant that comes to mind when thinking of winter berry color.   Legend describes holly growing from the footsteps of Christ with the red berries representing the blood he shed on the cross.  And long ago in Northern Europe, harsh winter winds were thought to howl with demons.  Holly was believed to have magical powers and, perhaps because it stayed evergreen, boughs placed above doorways were said to drive away evil. Today holly is used indoors and out to brighten mantles, floral arrangements, wreaths and swags.  Hollies can be enjoyed year-round in mixed borders and patio pots .     

Ilex x 'Rutzan' RED BEAUTY® pp#14,750,

 Ilex x 'Rutzan' RED BEAUTY® pp#14,750,    from Rutgers University, is one of my favorites. It stays naturally compact and pyramidal and is perfect for holiday containers! Even young plants of RED BEAUTY® will produce a healthy crop of berries. 

In colder climates, consider Ilex verticillata. Native to the eastern US and Canada and known as Winterberry, this holly loses its leaves in winter and thrives in soils wet with winter precipitation. It suckers freely to form dense thickets but also trims up nicely as a single specimen.  

Cedar Waxwing in Holly: Photo by Tony Pratt

The persistent bright red berries are especially attractive in arrangements…and to birds such as Cedar Waxwings and Thrushes. Missouri Botanical Garden    

Callicarpa 'Profusion' - Beautyberry

If red is not your color, consider the metallic violet purple berries of Beautyberry (Callicarpa 'Profusion'). The individual berries are quite petite but the clusters are good sized and wrap all the way around the winter-bare stems. Beautyberry works best in a mixed border where it has room to spread but, again, be prepared to share the berries with the birds.

Cornus mas - Cornelian Cherry

The Cornelian Cherry (Cornus mas) is actually a dogwood, not a cherry. I love mine for its multi-season interest. Masses of yellow flowers, while not overly conspicuous, put on a good spring show. By fall, elongated grape-size berries hang from the branches. Typically, birds discover the berries in the early part of winter, but I enjoy the show until then.

This year, I am tempted to try my hand at a Cornelian Cherry Marmalade, popular in Turkish cooking and said to be a tasty accompaniment to the holiday meal.

Gaultheria procumbens - Wintergreen or Teaberry

Wintergreen or Teaberry (Gaultheria procumbens) also flaunts extraordinarily bright red berries. White, late season flowers often linger on this non-invasive groundcover to contrast dramatically with the berries and glossy deep green foliage. Wintergreen remains supremely attractive year-round. Growing only a few inches high, it makes a perfect groundcover for an entryway or small space garden. (Don't forget to tuck in a few groupings of Tete-a-tete Daffodils for spring zing!).

Gaultheria miqueliana

Alternatively, plant wintergreen to soften the edges of patio pots.  If red berries aren't your thing, try Gaultheria miqueliana white berries and a similar habit.

Skimmia japonica

Even on a gloomy rainy day, as we are having today, I can look out my window and feel instantly brightened by the show of color. Skimmia, Euonymus, Viburnum, wild roses, Cotoneaster, Arbutus and Juniperus….the list of berrying plants goes on and on. I find the best source of inspiration is only as far as your local garden center, public park or arboretum. Zoos and university campuses often have fabulous plant collections and exploring their corners may be a good way for your family to turn Black Friday into Green Friday.

Juniperus chinensis  photo by Richie Steffen/Great Plant Picks

Next week: A quick break from winter color to discuss Gifts for Gardeners, than back the following week with winter buds.

Happy Thanksgiving everyone.

WARNING: There is NO reliable visual guideline for identifying toxic vs non-toxic berries. The ONLY way to know if a berry is poisonous, is to make a 100% accurate ID of the plant. Never teach children to pick fruit without direct supervision.   The American Association of Poison Control Centers manages a database of poisons of all types is available 24/ to provide assistance.



    





 

Winter Foliage Color



Leucothoe axillaris with burgundy red winter leaves

The subtleties of foliage color, berries, bark, and buds come into play during the winter more than other times of the year when opulent flowers dominate our line of sight.
For the next few weeks, I will highlight each of these aspects.
This week – foliage. Specifically, foliage that contrasts green (yes, I know green is a color, too).  

Nandina 'Gulf Stream'

When we think of changing leaf color, we tend to think of deciduous trees turning yellow, orange and red in fall. In the winter, many broadleaf evergreen plants also turn color. Color can vary between the orange-red of Nandina, the burgundy-red of Leucothoe, and to the chocolate-brown of lepidote Rhododendrons.   



winter foliage color of Rhododendron 'Checkmate'

  Additional color occurs in variegated plants such as Pieris 'Flaming Silver' or Daphne odora 'Maejima', as well as in blue and gold foliaged evregreens. 

Daphne odora 'Maejima' has bolder variegation than other D. odora

Regardless of whether you are starting with a clean slate or working with an existing landscape, there is sure to be a plant - groundcover, shrub, tree or perennial- to fit.



Pinkish purple color highlights the blue foliage of Andromeda 'Blue Ice' during the winter months

Here are some tips for success. 

Pieris 'Flaming Silver' has showy variegated foliage..and buds!

1. Look for color opportunities near your entrance. Because we spend more time coming and going than lounging in our yards, plant color close to where it will be seen the most.
2. Plants in full sun will have the boldest leaf color change.
3. For shade, variegated plants work best.
4. Seasonal patio pots are not just for summer annuals. Some of the best container plantings have very little annual color, relying on perennials, shrubs and even small trees for zing. Think of your container as a floral arrangement and let your creative juices flow with an artful arrangement of color and texture.
5. Plants used in pots can be planted into your landscape after the holidays.
6. Decorating for the holidays? Tuck a few sprigs of broadleaf evergreens into the holiday wreath hanging on the front door. With the same broadleaf evergreen planted nearby, a sophisticated put-together look is guaranteed. Wont your Mother-in-Law be impressed?!  

gold foliaged Chamaecyparis add brightness to winter.
Photo © Richie Steffen/Great Plant Picks 

Many studies have documented the effect of color on our moods. Red evokes excitement, energy and passion. Gold gives us warmth, joy and happiness. And, blue provides peace, tranquility and calm. A bit of planning and a trip to your favorite garden center is all you need to have winter color in your yard, and in your life.


Pieris 'Katsura' pp15,452 holds its red foliage color well

For more listen to our ( The Garden Girls- Karen Kemp-Docksteader and I) interview on Big Blend Radio's Garden Gossip with mother-daughter hosts, Nancy and Lisa. 

Next week...winter berry color

The Best Kalmia-Mountain Laurel

Long time favorite Kalmia' Olympic Wedding'

Crimped and perfectly shaped, I often refer to Kalmia flower buds as "little candy stars". Born in clusters, the buds become more and more prominent before opening in late spring or early summer. And as exciting as the buds, Kalmia  flowers offer their own degree of wow. The petals of Kalmia flowers are typically fused together in a chalice-shaped corolla, with many offering intricate patterns of banded color.

Kalmia 'Pinwheel' - striking bands of cinnamon red

The flowers of Kalmia , or Mountain Laurels, are among the prettiest of our native plants. They are members of the Heath Family (Ericaceae) which includes Rhododendrons, Azaleas and Blueberries.   Kalmia latifolia is found in mountainous areas of the United States from Maine to Florida and as far west as Indiana and Louisiana. Connecticut named Kalmia  as their State Plant and Pennsylvania named it their State Flower.


Kalmia latifolia adds color to a native woodland setting.  Photo courtesy of Tennessee Valley Authority

Colonists, including Captain John Smith in 1624, were quick to notice this beautiful woodland understory plant. Also called spoonwood, Native Americans used the hard wood to make spoons and early settlers found the strength of the wood useful for pipes, furniture and household items. In the 1700's Swedish explorer Peter Kalm, returned from a trip to the New World with specimen samples he had collected for his teacher, Carl Linnaeus. Linnaeus named the genus in Kalm's honor.

Native Kalmia latifolia  Photo by Gary Kaufman

Kalmia  foliage is glossy and can be medium green with yellowish stems to dark green with reddish-purple stems. Little-leaf forms have…little leaves. Little-leaf Kalmia  are derived from a botanical form (f. myrtifolium) which has slower growth and smaller leaves. The smaller leaves sit closer together on the stems and give them a unique texture.


Kalmia 'Minuet' is one of the best little-leaf forms


Kalmia 'Little Linda' Note the bright red buds and clear pink flowers.

Kalmia are more drought tolerant than Rhododendrons. In full sun Kalmia  plants will be denser in habit and flower more prolifically. In the southern regions, protect the plants from extreme heat and extend the life of the flowers by providing a bit of shade. Standard Kalmia work great in mixed borders where a larger and more open habit can be appreciated, while little-leaf forms make ideal foundation plantings. Kalmia flowers complement each other and a combination of cultivars within a mass planting adds interest without losing depth. Both standard and little-leaf forms types make fabulous informal hedges and mass plantings


The flowers of Kalmia 'Peppermint' resemble peppermint candies.

Although valued for ornamental characteristics, it wasn't until the late 1960's when Kalmia breeding began in earnest. Horticultural geneticists, such as Richard Jaynes, pursued Kalmia  breeding with a passion, and are responsible for many of the cultivars produced today. Briggs Plant Propagators has long worked with Jaynes and others to bring outstanding new cultivars to market.



Kalmia 'Starburst' one of the newest from Richard Jaynes



Understory groundcovers

Cyclamen coum image © Richie Steffen/Great Garden Picks

Merriam-Webster defines a groundcover as a replacement for turf. In my book, groundcovers serve an important, yet underappreciated role in the garden. They are the carpets under the furniture (trees and shrubs) of our yards - drawing attention without distracting from the focal elements of your landscape and softening the ground under our feet.
Rather than having a central trunk or cluster of woody branches, many groundcovers spread by underground stems called rhizomes. Other groundcovers form clumps that enlarge with time and grow together to form one large mat. Groundcovers provide color and texture in areas where other plants struggle, they are an easy-care weed suppressor, and they tie together different elements in our gardens.
If we go back to Merriam and reference groundcovers as a replacement for lawn, consider the areas under trees. Tree canopies can create dense shade and prohibit rainfall from reaching the ground, making it difficult for lawns to establish. Additionally, tree roots can over-compete for water prohibiting the success of larger shrub plantings. In these situations, the right groundcover thrives.
Moreover, unlike bare soil, groundcovers inhibit weed growth by blocking weed seed access to soil and light. A heavily mulched area can also suppress weeds however, mulch requires raking and replacement to stay fresh looking and the overall feel is sterile compared to the lush look of a groundcover.



Gaultheria procumbens

Groundcovers, by very nature, spread – and that is what we want them to do. However, in smaller areas we need the spread to be slow and controllable. The following four groundcovers fit this need, spreading slowly to fill small understory locations without demanding much care.

Gaultheria procumbens: Wintergreen. Crush a berry and you will instantly recognize the strong fragrance of wintergreen used in chewing gums. Native Americans used Wintergreen in a medicinal tea and it is sometimes called Teaberry.
  Wintergreen's white bell shaped flowers begin their show in summer and continue through fall. They last long enough to intermingle with the berries for a perfect holiday display where the vivid colored fruit rival the red of Santa's suit. Additionally, the glossy foliage takes on a burgundy hue in the wintertime. Hardy to USDA Zone 3.



Flowers and foliage of Gaultheria procumbens

  

Cornus canadensis

Cornus canadensis: Bunchberry. This diminutive member of the dogwood genus grows native in many parts of the United States. Cornus canadensis, or bunchberry, forms a loose mat of leaves and changing delights through the seasons.
In summer you will delight in the four petal-ed white flowers.

Orange red berries follow the flowers, and in fall the leaves turn rich burgundy red and persist through winter. Cornus canadensis provides a wonderful floor for other native and woodland plants. Hardy to USDA Zone 2.




  


Cyclamen coum

 Cyclamen coum: Hardy cyclamen are more diminutive than their florist counterparts. People often remark "how cute" they are, but don't let the size and delicate appearance fool you…these plants are tough! A bit of shade and a well-drained soil is all they need. Foliage patterns vary from minor spotting to complete pewter coloring. Flowers can be white to rose-pink. Cyclamen are wonderful understory for deciduous shrubs or small trees. The foliage and flowers stay under 6" tall. Hardy to USDA zone 4




Adiantum venustum

 Adiantum venustum: Himalayan Maidenhair Fern. A fern as a groundcover? Why, yes! This award winning Maidenhair fern will cover the ground in delightful lacy-ness. Bright green foliage lays in striking against black-as-night stems. Additionally, Adiantum venustum is evergreen – the fronds persist through the winter and, in the early spring, the new fronds emerge with bronze overtones. Hardy to USDA Zone 5



Each of these small-scale understory groundcovers will gradually spread but never at such a rate as to be a maintenance headache. They provide year round cover and delightful seasonal interest.


Planting tips:
Stick with one type of groundcover in an area. More than one and the planting will look weedy.
 

Variegated Pachysandra and Crocus

For extra interest, interplant spring bulbs. Small narcissus or crocus will pop up out of the groundcover for spring delights. After they bloom, you can tuck the dying foliage into the groundcover to hide it.
Don't skimp in the initial planting. Larger plants will always have more visual impact, but using you dollars to buy more small size pots allows you to tuck the individual plants closer together for a fuller look.

When planting in rows or in a block, make sure you stagger the plants.    
            x x x x x
             x x x x
            x x x x x