Even for the most experienced Master Gardener, the term keystone plant may be new. Thrown around by ecologists, a keystone plant is one with high ecological value – one that is significant as a food source. In fact, the National Wildlife Federation (NWF) states that 96 percent of U.S. terrestrial birds rely on insects supported by keystone plants.  Interestingly enough, in Wisconsin, trees top our list of keystone plants.

In a recent article by Jennifer Rude Klett for the Milwaukee Journal Sentinel, oak trees – to include white, bur, swamp white, chinkapin and black -- stood out on top of the list. According to the NWF’s list of keystone plants by ecoregion, the white oak Quercus alba is listed as the number one keystone plant for most of the state, in part because of its role as a host plant for up to 450 species of caterpillars.

Caterpillar diversity is the main reason a tree may be listed as a keystone plant. According to the article, in addition to oaks, other trees that top the list include American plum, black cherry, chokecherry, river birch, sweet birch, bitternut hickory and Eastern white pine. Sugar maple, Wisconsin’s state tree, is another keystone plant that acts as a host plant for well over 200 caterpillar species. Interestingly, silver maple and box elder, also a member of the maple family, along with Eastern cottonwood, are also keystone plants, according to the NWF. Those three, however, are sometimes thought of as “junk” trees to be removed but nonetheless offer high wildlife value.

Neil Diboll, a noted Wisconsin expert on keystone plants, stated that “most gardeners do not know about keystone plants because our culture does not focus on the ecology of our gardens and landscapes. You need a diverse mix of trees, shrubs and flowers, along with some grasses and maybe some sedges, to create a complete habitat for pollinators, birds and other wildlife. It’s all about the diversity.”
To learn more about keystone plants…and trees, read the complete article.

Narrow upright plants provide screening with a relatively small footprint. Trautman juniper is suited to hot dry locations and grows 12’ tall by 4’ wide. It is resistant to cedar apple rust and deer.

Year-round greenery is welcome but help boost the beauty and enjoyment of your landscape with plants that support pollinators, attract birds, and provide several seasons of beauty.

The four-season Obelisk serviceberry grows 12-15’ tall and 3-4’ wide. Its white spring flowers are followed by purple fruit in June that you and the birds can eat. It ends the season in a blaze of color and once the leaves drop exposes smooth gray bark.

A close relative, the chokeberries (Aronia) are also known for their multiple seasons of beauty. Lowscape Hedger® is upright three to five feet tall and just two to three feet wide. Like the others, it has white flowers in spring and great fall color. This adaptable plant grows in sun or part shade and tolerates wet or dry soil.

Laced UP® elderberry has the foliage of black lace but is upright and narrow, growing six to eight feet tall and three to four feet wide. Its lacy purplish-black foliage makes a nice backdrop for the pink summer flowers, adding to its ornamental appeal.

The narrow columnar apples make a good option for those interested in growing edible plants. Urban®, North Pole™ and Golden Sentinel™ apples are a few narrow upright varieties to consider. Plant two different varieties for fruit to form.

A vine-covered trellis is an excellent screening option for narrow spaces. Consider growing two different vines like climbing roses or Major Wheeler honeysuckle with clematis to double the floral impact or extend the bloom time. Use an annual vine like hyacinth bean, Malabar spinach, scarlet runner bean or Solar Tower sweet potato vine the first year or two. They’ll provide quick cover while the perennials become established and cover the trellis.

Dress up fences with plants. Shrubs, ornamental grasses, flowering perennials can soften the structure and add texture and color. Include pots of tropical plants to create a tropical paradise and annuals for added color.

Espalier fruit and ornamental trees are a great way to add the fruiting or beauty of larger trees into a smaller space. These are options only for those willing and able to regularly prune to maintain the desired size and shape.

Green wall planters mounted on the fence can add edibility or color at eye level. These typically have a very small volume of planting mix and require frequent watering. Irrigation systems that provide water from top to bottom greatly reduce maintenance and increase success.

Make sure the plants selected thrive in the growing conditions and will fit the available space when mature. Less grooming, pest management and care will be needed to grow them into healthy and attractive specimens.

Before placing any plant or structure in the ground, call 811 or file online at diggershotline.com at least three business days in advance. Diggers Hotline will contact all the appropriate companies who will mark the location of their underground utilities in the designated work area.  This eliminates the danger and inconvenience of accidentally knocking out power, cable or other utilities while creating a beautiful landscape.
 
Please remind others to do the same. Since this important step is often overlooked, April has been designated as National Safe Digging Month. It serves as a reminder to always contact Diggers Hotline whenever undertaking any landscape project, large or small.
 
Melinda Myers has written more than 20 gardening books, including The Midwest Gardener’s Handbook and Small Space Gardening. She hosts The Great Courses “How to Grow Anything” DVD series and the nationally-syndicated Melinda’s Garden Moment TV & radio program. Myers is a columnist and contributing editor for Birds & Blooms magazine. Her web site is www.MelindaMyers.com.

​Enjoy the fragrance and beauty that lilacs bring in spring.  Today with about 30 different species, varieties have been developed for heat tolerance, reblooming flowers, compact size and even growing happily in a container on a balcony.

Clusters of small, four-lobed flowers are developed into cone-shaped to narrow pyramid clusters (panicles, i.e., branched inflorescence) that stand out from the green heart-shaped leaves. These flowers can be single or double in every imaginable shade of lilac and purple to hues of red, pink, blue, yellow, cream and white—even picotee (white-edged, deep purple ‘Sensation’). Its color may also change from bud to bloom as the flower matures.

Lilacs grow best in full sun, with good drainage and fertile, slightly alkaline soil. Begin with testing soil drainage by digging a hole 8 inches across and 12 inches deep and filling it with water. If any water remains in the hole after an hour, choose another planting area. After following the planting directions on the tree’s label, water lilacs regularly for the first couple of years—at least 1” of water a week.

Ongoing maintenance: Cut off spent flower-heads within a month after bloom to help set more flowers for next year. Cut off root suckers to keep the common lilac from spreading into a colony. Prune out any dead or broken branches from storm or winter damage.  Pruning annually is not necessary, but to rejuvenate an overgrown plant or one that blooms sparsely, cut 1/3 of the oldest branches back to 12-15” from the ground. Do this over a 3-year period to refresh the plant without sacrificing blooms.

Powdery mildew can be unsightly but generally does not harm the plant. You can make a spray of 2 tablespoons of baking soda in a gallon of water with a couple of drops of Ivory liquid. Spray it on the leaves, but not if the temperature is over 80°. The alkalinity of the solution helps to kill the fungus.

Early Spring maintenance: Apply granular organic fertilizer at the base of the plant and water it in well. Buds are set the previous year, so the fertilizer feeds this year’s leaves and next year’s blooms.

Fall maintenance: If your soil is very acidic, add garden lime. Rake fallen leaves from around the plant, and if you had powdery mildew or any disease, bag leaves and toss in the garbage.

Did you know, the stems of the common lilac have a spongy pith that can be removed, leaving hollow tubes that were used to make pan-pipes? In 1753, Carl Linnaeus first described the lilac genus, Syringa, from the ancient Greek word syrinx, meaning pipe or tube.

Credit to https://ngb.org/year-of-the-lilac/

Contributed by:  Vicki Gee-Treft, Master Gardener Volunteer

Regular pruning throughout the life of the tree promotes healthy growth, maintains the shape of the canopy, and reduces stress on the tree.  Dead, diseased and damaged branches should normally be removed right away.  One exception is Oak, which is susceptible to Oak Wilt disease, and best pruned while dormant. 
 
Early spring is an ideal time to identify branches and limbs requiring removal.  Some trees such as Maple may bleed sap, but this will self-seal and is not harmful.
 
“Proper Tree Pruning” published by the WI Department of Natural Resources illustrates some key pruning basics.
 
More resources:

• Wisconsin DNR information on Oak Wilt
• Wisconsin DNR Information on Firewood Rules
• Wisconsin Horticulture – Extension Division – Trees and Shrubs​

Although it doesn’t seem like the optimal time to be gardening, February is actually a great time to be out pruning your trees and shrubs to make them more structurally sound and aesthetically pleasing.

Why prune now? Whenever you prune, you create wounds that potentially can serve as entry points for disease-causing fungi and bacteria. If you prune in the spring and summer (when it’s warmer and often wetter), these organisms are very active and more likely land on fresh pruning cuts and infect. When the weather is colder and drier (as it tends to be in February in Wisconsin), disease-causing organisms are much less active and the chances of them infecting though pruning cuts is much reduced.

How do I go about pruning? Check out University of Wisconsin Garden Facts XHT1013 (Pruning Evergreens), XHT1014 (Pruning Deciduous Trees) and XHT1015 (Pruning Deciduous Shrubs) for pointers on how to prune.

Prune only when it’s dry, and decontaminate pruning tools between cuts (or at a minimum between each tree or shrub) by treating them with 70% alcohol (e.g., rubbing alcohol right out of the bottle, spray disinfectants containing ~70% alcohol) or (in a pinch) 10% bleach. Decontaminating tools kills off disease-causing organisms that you might pick up as you prune. Once done pruning, if you’ve used bleach, be sure to thoroughly rinse your tools, and oil them to prevent them from rusting.
​
By pruning regularly and taking a few simple precautions as you do, you will end up with trees that are beautiful, structurally sound and healthy.

The program handouts are now available.  Listed below and on our 2020 Events Handouts page. 

• PDF of PowerPoint Slides
• Native Plant List from Minnesota DNR
• Link to an article about Nativars  
• More Phenology  Planting Tips ​
  
• UW Soil and Forage Lab - link for soil tests (note as of 3/23/20 tests are suspended due to COVID-19)
• Some additional recommendations on reading: 
  • Braiding Sweetgrass: Indigenous Wisdom, Scientific Knowledge, and the Teaching of Plants  by Robin Wall Kimmerer  It’s a bit of a cultural exploration of the relationship between plants, animals, the earth and humans.  More like essays than a look up info book.
  • Grow Native, Lynn Steiner  This author writes and provides recommendations on how to incorporate natives into our gardens. 
  • Bringing Nature Home and Nature's Best Hope, Doug Tallamy
  • The Living Landscape, Dick Darke and Doug Tallamy
    
    

This program covered what, when and where to cultivate native plants that provide food for butterflies, song birds, hummingbirds and beneficial insects.   By using your observations you can know the best time for planting, the blooming cycles of plants, and the emergence of insect pests.  All will help you become a more natural gardener. 

​If you are traveling in the Philadelphia area I highly recommend this list of gardens, all quite different.  Seeing woodland spring ephemerals in different settings taught me a new appreciation for what I tend to take for granted here at home.   Anytime during their long growing season these gardens will teach, display and provide pleasure to their visitors.  

​Morris Arboretum – As the name implies the arboretum is a teaching and research facility of the University of Pennsylvania.  It is set on the historic grounds of the summer home of John and Lydia Morris.  They have informative displays of trees, shrubs, and woodland perennials.  

​Longwood Gardens – One of many du Pont family gardens in the area.  The gardens are spread about on 1,100 acres of highly manicured display gardens.  We were there for six hours, more than enough time to see almost everything and spend time in their excellent garden shop.  According to their website they raise 75 percent of the plants used in their displays onsite producing about 110,000 plants of 1,000 different varieties.  Nearby is Kennett Square, a tidy small town with many retail shops and restaurants. 

​Mt. Cuba Center – The Center is set in the rolling hills of the Delaware Piedmont near Wilmington.   The property was developed by Mr. and Mrs. Lammot du Pont Copeland.  Mrs. Copeland is quoted in their intention for the property: “I want this to be a place where people will learn to appreciate our native plants and to see how these plants can enrich their lives so that they, in turn, will become conservators of our natural habitats.”.  If you go, I recommend scheduling a tour by one of their very knowledgeable tour guides.  If you can’t go to Mt. Cuba Center, you can still learn much by going to their website.  I have bookmarked as one of my favorites the native plant finder.  

​Winterthur – The home of Henry Francis du Pont, the 1,000 acres near Wilmington, DE includes 60 acres naturalist gardens, a research library, shops, museum, and the mansion chock full of American textiles and furniture.  The gardens are more in the background of Winterthur given all the other attractions of this property.  

​Chanticleer  - This garden was the last we visited, and I think the best.  Chanticleer is set on 47 acres of the former home of the Rosengarten family, members of the family still guide the foundation that manages the property.  This unique property employs seven Horticulturists who are each responsible for an area of the grounds.  Chanticleer advertises itself as a pleasure garden and definitely lives up to that name.  We felt as if we were invited guests, the horticulturists and grounds staff were about the grounds ready to answer our questions.  

What a treat to have visited these gardens, each one unique in its own way.  And the Winnebago Master Gardener Volunteers are wonderful traveling companions.  

​Author:  Sue Reinardy, UW-Extension Master Gardener Volunteer

The trees most likely to die from oak wilt infection are in the red oak group, including northern pin oak, northern red oak, red oak and black oak. The white oak group is more likely to survive infection and includes bur oak, swamp white oak, white oak and English oak.
Tree paint or wound dressing is not normally recommended on pruned or wounded surfaces, but for damaged oaks an immediate light application of these products may be the only defense against oak wilt infection from April through July.
Pruning in spring can be damaging to any deciduous tree because their energy reserves are low as they produce new buds and leaves following the winter months. In general, the best time to prune is in winter when trees are dormant. 
As of January 31, oak wilt has been found in all Wisconsin counties except Ashland, Iron, Forest, Taylor, Door, Kewaunee, Calumet and Manitowoc counties. Several of these counties contain the highest abundance of healthy and productive oak forests in the state. Taking recommended precautions will help keep them that way for years to come.
Oak wilt and other diseases move easily on or in firewood logs year-round, so keeping firewood local, or purchasing Wisconsin-certified firewood, is another important component of protecting trees and keeping forests healthy. Visit the DNR firewood page for more information and a directory of certified firewood vendors.
More information, including a recently released oak wilt video, is available at the DNR oak wilt page. Additional information about proper pruning techniques is available from community foresters or through DNR resources such as this tree pruning poster.