Downy Mildew Causing Many To Lose Impatiens

Last year, we encountered a widespread, extremely destructive disease called Impatiens Downy Mildew, affecting Impatiens walleriana (common impatiens). It is an aggressive and easily spread disease that causes the plant to lose its leaves and eventually die. Some of you may have encountered this at your property last summer. Downy mildew is not easy to detect in its early stages, so by the time you know you have it, it’s likely to have infected all of your impatiens. The disease has impacted impatiens in other parts of the United States for several years now, but first became a problem here during the 2012 planting season.

Infected plants will develop yellow spots on the leaves and appear to be unhealthy. An examination will reveal white spores on the underside of the leaves, which soon will begin to drop from the stems. The disease can be controlled in a greenhouse environment with use of fungicides, but the effects of the fungicides lessen with time. Impatiens that appear healthy upon purchase can deteriorate quickly once they’re planted at home. Established, downy mildew spores can be spread by the wind, blowing from site to site easily infecting other impatiens. Fortunately, the disease does not spread to other plant varieties, including New Guinea impatiens. Because the disease is so difficult to prevent and control, the only real solution seems to be not planting impatiens.

Alternatives

Fortunately, there are many common shade-loving annuals that make great alternatives to planting impatiens. New Guinea Impatiens, Reiger Begonias, Coleus, Caladium, Tuberous Begonia ‘Non-Stop’ varieties, Impatiens Hybrids ‘Fusion’ series are just a few of the wonderful alternatives to select from

Perennials are also an excellent alternative to seasonal annuals. Although the upfront cost may be higher, selecting plants that return each year provides a lower-maintenance, longer-lived, sound solution. Two perennial groundcovers we recommend are Creeping Vinca, covered with periwinkle blue flowers in spring, and Lamium, a lower-growing groundcover with interesting foliage and lovely white, pink or purple flowers. There are many shade-loving perennials to choose from that bring color and are suited to different soil types. Dry shade areas will benefit from tough Hosta like ‘June’ and ‘Paradigm’, with fancy foliage and lavender colored blooms. Wet areas will allow Astilbe to thrive; ‘Purple Candles’ has bold fuchsia-pink flowers, while ‘Peach Blossom’ has delicate peach-pink. Well-drained conditions would work perfectly for Coralbells like ‘Caramel’ and ‘Tiramisu’, which have beautiful leaves of orange, purple, yellow and green.

Impatiens have been a garden staple for many years and it is unfortunate that the disease has decimated our area. We look forward to the day when a downy mildew-resistant strain of Impatiens walleriana is developed and we can confidently bring them back.

Case Study: Cottage Garden With Curb Appeal

Our clients purchased this charming 1920’s Dutch colonial house with plans of making it their own.

The existing landscape consisted of a traditional front lawn with overgrown shrubs and a scattering of perennials. Our clients wanted to simplify the maintenance, add curb appeal and create a garden for all to enjoy.

After remodeling the home’s façade, they were ready for a fresh look for the front yard. We removed the lawn and plantings, saving some perennials to transplant. Removing the overgrown plant material revealed a beautiful stacked limestone retaining wall. A new paver sidewalk and sitting area were installed to provide a place for the homeowners to enjoy their garden and chat with passersby. Stepping stones tie the areas together and allow one to meander through the lush cottage garden. A mixture of evergreens, hydrangeas, roses, grasses and perennials were added to create a year-long showcase and welcome birds, bees and butterflies. Containers of colorful annuals, landscape lighting and drip irrigation complete the garden rejuvenation.

Plants for a Winter Wonderland

Say goodbye to the dreariness of winter, by installing a fantastic plant (or two!) that will bring plenty of inspiration and interest in your winter garden.

Paperbark Maple, Acer griseum, is a low-growing, small deciduous tree with scarlet red fall color and striking cinnamon-colored bark that exfoliates.15-20’h x 10’w. Full sun-part shade.

Kousa Dogwood, Cornus kousa, is a terrific deciduous tree with multi-season interest. In spring, it’s covered with pretty, star-shaped blooms, in fall, leaves turn a beautiful reddish orange and in winter, it shows off its exfoliating bark in shades of gray, tan, brown and orange.Many selections are available. 20-25’ x 20-30’w. Part shade-full sun.

Blue Princess Holly, Ilex x meserveae ‘Blue Princess,’ is a beautiful evergreen shrub with shiny, spiny, dark green leaves. Paired with Blue Prince Holly, will bear bright red berries in winter. 4-6’h x 4-6’w. Full sun-part shade.

Globe Blue Spruce, Picea pungens ‘Glauca globosa’, is another evergreen shrub that offers distinctive silvery blue needles year round that have the added benefit of deer and rabbit resistance. 3-5’h x 4-6’w. Full sun.

Golden Mops Threadleaf Falsecypress.

Falsecypress, Chamaecyparis, are slow-growing, finely textured, touchable evergreens that are deer and rabbit resistant and serve as wonderful specimens in a protected, sun to part shade location. Sullivan Falsecypress C. lawsoniana ‘Sullivan’, has softly drooping branches and a fluffy yet narrow form. 15’h x 8’w. Golden Mops Threadleaf Falsecypress, C. pisifera ‘Mops’, a pretty little plant with a low-mounding, pyramidal form and brilliant yellow, thread-like foliage. Best color shows when planted in sun. 5’h x 3’w. Fernspray Cypress C. obtusa ‘Filicoides’ has an upright form and an open, irregular habit and unusual sprays of lush, fern-like foliage. 5′h x 4′h.

Coral Embers Willow, Salix alba ssp. Vitelline Britzensis, is a deciduous shrub with fantastic bright orange stems. As with all willows, it requires consistently damp soil with good drainage. 4’h x 4’w. Full sun.

Maiden Grass.

Ornamental Grasses such as Maiden Grass Miscanthus, Switch Grass Panicum and Feather Reed Grass Calamagrostis shine in summer and fall, and when left uncut in the winter, offer structural interest with their dried flower plumes and golden tan foliage. They come in a variety of shapes and sizes, and thrive in full sun.

Case Study: Restorative Garden at Three Crowns Park

Nature’s Perspective recently completed construction of a restorative water garden at Three Crowns Park, a senior community in northwest Evanston that has served its residents for over a century.

Origins

In the early spring of this year, Ariel Schrodt, a new resident of Three Crowns Park, had a vision of creating a memorial garden for his late wife, Ellen. He wanted to recreate the pond that he and his wife had lovingly built together at their previous residence. He donated several tons of Chilton Limestone boulders that he had used to build his own pond.

Nature’s Perspective was contacted to work alongside the community at Three Crowns to turn his vision into a reality. We began the process with multiple concepts and renderings to show how his vision could be incorporated into a restorative garden.

Throughout the summer, the community at Three Crowns came together to raise funds by selling memorial pavers and other donor items.  In late summer, the community’s fundraising goal was reached, and our design for a restorative water garden was selected.

We began construction in October. Being a large site, access was easy, but utilities were not. We were challenged by having to incorporate our garden into the existing irrigation system. Other obstacles included wiring a GFI outlet for the water feature, routing lighting cable, and securing benches to a solid foundation.

The end of construction coincided with the 5^th anniversary of Three Crowns’ 2007 facility expansion. Despite the cold and windy weather on October 29^th, many made it outside for a ribbon cutting ceremony.

Restorative Garden Design Principles

Outdoor spaces of all sizes and settings are designed based on a set of principles. An outdoor area at a senior community must be easily navigable on paths of a smooth hard material. It must also allow access, circulation, and full use by persons with disabilities. Beyond accessibility, these photos show other design principles that came into play in this design:

The Journey

These photos show how the layout invites exploration. The path was designed with materials that replicate the colors of a forest floor. It winds through other garden elements to create hidden views.

Sensory Awakening

The senses are brought alive in this space, especially when viewed at night. Moonlighting is a landscape lighting technique that casts shadows of tree branches and leaves onto the ground. Here, moonlighting is used for wayfinding.

Self-Awareness

A memorial garden can be the perfect place for quiet reflection. Three seating areas in the restorative garden provide safe, protected areas surrounded by lush plant life changing by the season. We can’t think of a better place to sit and enjoy nature.

Ariel Schrodt (center) at the ribbon-cutting ceremony with his son (at right) and a friend (at left).

Spring-Flowering Bulbs With Deer and Rabbit Resistance

Labor Day, the traditional end to summer, has come and gone. For us at Nature’s Perspective, we have started the fall season. The cool weather has added to the feeling that fall is here.

Fall is a wonderful time to establish new plantings or reconfigure existing gardens. Warm days lead to cooler nights and rainfall becomes more regular. Trees, shrubs and perennials have started to slow down growth and begin their winter dormancy. The leaves are starting to change color and drop, but below ground the root system is continuing to grow, repairing any damage from transplanting or the harsh summer. This continues until the ground freezes. Even the Kentucky bluegrass lawns are responding to the cool weather with fresh green growth, a last hurrah before winter.  However, at this time of year we should actually THINK SPRING! Spring-flowering bulbs can only be planted during the fall. Everyone is familiar with colorful, showy Tulips and cheerful Daffodils that are the mainstay of the bulb garden. There are many other spring-flowering bulbs that are not as well known, but definitely should be in everyone’s garden. We created a list of some lesser known bulbs that are also resistant to deer and rabbits! Think about the possibilities of adding small pockets or large swaths of color to your garden starting as soon as the snow melts in March with Snowdrops and Winter Aconite and continuing until the Allium finish the show in June.

Listed in order of their appearance, you can count on the following bulbs to bloom and perform beautifully in your garden.

MARCH

Snowdrop, Galanthus nivalis, do well in our area and emerge very early. The small, three-segmented, drooping white flowers are 5″ tall and stand out dramatically above their silver-green foliage.

Winter Aconite, Eranthis hyemalis,  is another early bloomer. The solitary, yellow buttercup-shaped flowers grow 6″ tall and are surrounded by bright green bracts that look like a collar around the blossom.

Reticulated Iris, Iris reticulata, has little vibrant purple blooms with a gold stripe appear above thin-straplike leaves. 8-12 inches tall.

Glory of the Snow, Chionodoxa, are low growing plants, reaching 4-6″ high with grass-like leaves that appear the same time as the flowers. Star-shaped flowers face upwards and last two weeks or more, and are available in white or blue. (March/April)

APRIL

Scilla, Scilla siberica, also called ‘Squill’, has vivid blue flowers and stands about 5″ tall. You can see some strikingly beautiful and very large drifts in many North Shore gardens where they have been naturalizing for many years. Some varieties are available in pink and white, but the blues are spring time knock-outs.

Windflower, Anemone blanda, is a charming border plant with daisy-like flowers that comes in a variety of blues, pinks, violets and white. The foliage resembles parsley and the plant stands about 6″ tall.

Grape Hyacinth, Muscari armeniacum, is the largest of the minor bulbs with tiny deep blue flowers densely clustered, like miniature grapes, on a firm stalk. The flower cluster is about 5″ long and the plant grows to 7″ or 8″ tall. They bloom a long time and produce a striking effect when planted in drifts.

Species Tulips, Tulipa spp., bloom in early spring and are smaller in size than the better-know hybrid tulips. Growing only 4-12” tall, they nonetheless come in many shapes and colors, and naturalize better than hybrid tulips in the garden. T. greigii grows 8-12 inches tall and blooms in mid spring, and is available in pink, yellow, orange, red, ivory and peach. T.  linifolia grows only 4 to 6 inches tall with vibrant red flowers.

MAY

Camas Lily, Camassia leichtinii, is a mid-sized plant that sends up slender purple, star shaped flower stalks atop its grasslike leaves.  Plant these in an undisturbed area, and they will naturalize in your garden for years. Foliage dies back in early summer. 24-32”h.

Crown Imperial, Fritillaria imperialis, are large plants that send out stately, impressive 3-foot tall flower stalks. Nodding whorls of colorful flowers in red, yellow or orange red are topped by a crown of spiky, glossy leaves. Great for the back of the border or in a location you want to make a bold statement.  

JUNE

Ornamental Onion, Allium spp., is naturally deer-resistant and comes in different forms and sizes. Purple Sensation Allium  has 2? to 4? diameter purple globes on sturdy 24-30” stems in early June. Globemaster Allium is a tall and architectural plant, with, huge, globe-shaped purple flower heads on 3- to 4-foot stems. Beautiful next to peonies and irises.

A Plant You Should Know: Black Lace Elderberry

Looking for a dramatic plant to serve as a focal point in your garden? Think Black. Black Lace Elderberry, that is!

Black Lace™ Elderberry (Sambucus nigra ‘Eva’ ppaf) is fairly new to the United States, introduced in 2006. One could easily mistake this plant for an exotic Japanese Maple, given its lacy, finely-cut leaves that are purple-black in color. But unlike a Japanese Maple, it is easy to care for and thrives in full sun.

In early summer, creamy pink, domed flowers appear, contrasting beautifully with the dark foliage (the above photo was just taken in our nursery in full sun). The flowers will turn into black-red, edible berries in fall, which you can snack on, or leave for your birds to enjoy. An added extra is its deer resistance.

Black Lace Elderberry came to our nursery several years ago as a trial plant. It has proven to be very cold hardy. Its mature size is about 6-8 feet high and just as wide. It can be pruned yearly to maintain a preferred size, or trained into a tree.

Beautiful, easy to care for, adaptable as a focal point or a hedge and resistant to deer? Now that’s one plant you should know.

Clear The Way! De-Icing with Care

With the bone-chilling temperatures and icy conditions of winter, we are often asked what products we recommend to melt ice or improve traction on stoops, steps, walkways and drives. Many of the items on store shelves are harmful to concrete, mortared areas, pets and the environment.

Sodium chloride, commonly known as rock salt is inexpensive, readily available and works at temperatures as low as 20 degrees Fahrenheit. However, it is the most harmful de-icer to plants and animal paws. Potassium Chloride, which is also used in fertilizers, will not harm plants but works more slowly than rock salt. Both are harmful to concrete, mortared areas and other natural products such as bluestone. Calcium chloride melts faster than the others, works down to 5 degrees Fahrenheit and is one of the least harmful salts to concrete, but is damaging to plants. One of the newer products on the market is magnesium chloride. This is your best bet if you want a de-icer that works quickly, won’t harm your concrete and paved areas, and is effective to 13 degrees below zero. It is important to remember to use each of these products as directed.

Environmentally friendly skid-proofing agents such as sawdust, peanut hulls, ground bark, ashes, gravel and sand can be used in conjunction with de-icers. They don’t dissolve in water and can be swept up for re-use, or swept into the lawn or planting beds without harm to plants. Owners of pets are particularly concerned about the toxicity of de-icers and their affect on sensitive paws. Pet-friendly products such as Safe Paw is considered to be pet, child and environmentally safe. This and similar products are chloride-free so it won’t harm your concrete, paved areas, lawns or plants.

In general, don’t over-apply salts. Used in excess, they may harm your plants and can damage concrete, mortared areas and natural stone products. Avoid shoveling snow from salted walks onto plants and know the ingredients in the de-icer you buy. Use gypsum calcium sulfate for areas where salt accumulation is heavy in the fall and the following spring. Irrigate well in order to wash away the salt and decrease the potential damage to your planting beds. Finally, keep salt away from sensitive plants such as azaleas, crabapples, dogwoods, forsythias, hollies, maples, rhododendrons, and yews.

Evergreen Accents

Summer’s splendor has come to an end. The lushness of lawns, trees, shrubs and flowers has faded, but a garden should be showing a quieter side just as beautiful as the previous season. Every garden should have its share of plants that provide interest during Chicago’s long winter season. Evergreens provide winter interest because they hold their needles through the winter months. They are, of course, the staples of the landscape; boxwoods and yews cover foundations with their green lushness. But evergreens come in all sizes, textures and colors, and can be used as specimen accents through the landscape. It’s fun to put a few small specimens in the perennial garden for a winter effect, or use a larger plant to add drama at the back of the bed. Here are a few of our favorites photographed up close, during a stroll in our nursery this afternoon.

Mops Golden Cypress Chamaecyparis pisifera ‘Mops’ is a pretty little plant with a low-mounding, pyramidal form and brilliant yellow, thread-like foliage. Best color shows when planted in sun; it turns green in shade.  60″ tall x 36″ wide.

Hinoki False Cypress Chamaecyparis obtusa Some have described the way the needles are held on this unusual, slow-growing plant as resembling coral formations. Especially attractive in a Japanese garden. Its holds its dark green color best in part shade. 8’ tall x  4’ wide.

Sullivan Falsecypress Chamaecyparis lawsoniana ‘Sullivan’ has softly drooping branches that provide a semi-pendulous habit. This fluffy yet narrow evergreen grows well in sun to part shade. Tips turn a bright red-orange in cooler months. We feel it performs better in this area than a Canadian Hemlock. 15′ h x 8′ w.

Blue Star Juniper Juniperus squamata ‘Blue Star’ is a little plant with its fantastic, bright, steel-blue needles. Low-growing, slow-growing, mounded in form, it makes a great accent in a sun-loving rock garden, or as a low border plant. 24″ x 36″w.

Hetz Juniper Juniperus chinensis ‘Hetz Columnaris’ is tall and strong, yet delicately textured, with an upright, pyramidal habit and emerald green foliage. Dense, tight habit makes this plant useful as a screen. Best in sun. Blue fruit are very attractive in the fall, turning golden brown. Distilled juniper berries are the source of gin! 10′ h x 5′ w.

Globe Blue Spruce Picea pungens ‘Globosa’ is a bright blue dwarf spruce with a neat rounded habit, flat-topped and densely branched. A beautiful sun-loving specimen deserving of a place by the front door or a special spot in the garden. 36″ tall x 36″ wide. 

Mr. Bowling Ball Arborvitae Thuja occidentalis ‘Bobazam’ is an delightful little plant that holds it attractive, unusual sage green color on soft, feathery leaves all year. This plant forms a perfectly round, compact globe. Who can resist its name? Loves sun. 24″ tall x 24″ wide.

Fire Chief Arborvitae Thuja occidentalis ‘Congabe’ is a little fireball, compact, and round, with distinctive foliage coloration of green and yellow with pinkish-red tips. Best coloration is achieved when sited in a sunny location. Never needs pruning. 36″ high x 36″ wide.

A Nearby, Noteworthy Garden Gem

The Shakespeare Garden in the 1930s.

Are you aware of a hidden garden gem located on the Northwestern University campus in Evanston, or of its historical significance?

This garden, a project of The Garden Club of Evanston, was established in 1915 to celebrate the ties between England and America. It also commemorated the 300^th anniversary of Shakespeare’s death.

The Shakespeare Garden was designed by Jens Jensen, the renowned Danish-American landscape architect and conservationist who had an office in Ravinia. It is one of only two formal gardens that he designed. All of the trees, shrubs, perennials, annuals and herbs in it were plants mentioned in Shakespeare’s plays. The 70- by 100-foot space contains flowers, shrubs, trees and herbs well-suited to our Midwestern climate, such as old roses, hollies, daffodils, nasturtiums and rosemary. 

The garden is maintained to this day by The Garden Club of Evanston.

The garden features plants mentioned in Shakespeare's plays.

Use this link to find out more about this urban oasis.

www.northwestern.edu/observer/issues/2004-10-07/garden.html

Plant Minor Bulbs for Spring Color, Deer/Rabbit Resistance

The most commonly used spring flowering bulbs are the ‘major bulbs’ such as daffodils, tulips and hyacinths. However, there is a whole group of ‘minor bulbs’ that provide such reliable color that most gardens would benefit from including them when planning for early spring color. The bulbs are tiny and the plants are small, rarely more than six inches in height, so a large number of bulbs are needed in order to make a visual impact.

The term ‘bulb’ includes a variety of plants with a large storage root (or stem) from which the plant grows every year. These little wonders of nature require only moisture and rising temperatures to end their dormancy and begin to grow. This means that bulbs are generally an easy and fool-proof garden plant. Minor bulbs also tend to be very resistant to deer and rabbit damage.

Minor bulbs should be planted during the fall, in drifts or masses, about 3”-4” deep. They can be planted in flower beds or shrub beds where they’ll emerge and bloom before the perennials get started and before deciduous plants leaf out.

Some of the prettiest minor bulbs, listed in order of the appearance in a garden, are:

Snowdrop (Galanthus nivalis) Snowdrops do well in our area and emerge very early. The small three-segmented, drooping white flowers are 5” tall and stand out dramatically above their silver-green foliage. (March)

Winter aconite (Eranthis hyemalis) is another early bloomer. The solitary, yellow buttercup-shaped flowers grow 6” tall and are surrounded by bright green bracts that look like a collar around the blossom. (March)

Glory of the Snow (Chionodoxas) are low growing plants, reaching 4-6” high with grass-like leaves that appear the same time as the flowers. The blue star shaped flowers face upwards and has a central white eye, lasting two weeks or more. (March/April)

Crocus (Crocus) naturalize exceptionally well, creating an expanding carpet of bright colors as the years go by. Their purples, lavenders, whites and yellows are a clear signal that spring in on its way. These are the only minor bulbs that we’ve listed that the rabbits eat. (March/April)

Scilla (Scilla siberica), also called ‘Squill’, this vivid blue flower is about 5” tall. You can see some strikingly beautiful and very large drifts in many North Shore gardens where they have been naturalizing for many years. Some varieties are available in pink and white, but the blues are spring time knock-outs. (April)

Windflower (Anemone) is a charming border plant with daisy-like flowers that comes in a variety of blues, pinks, violets and white. The foliage resembles parsley and the plant stands about 6” tall. (April)

Grape Hyacinth (Muscari armeniacum) is the largest of the minor bulbs with tiny deep blue flowers densely clustered like miniature grapes on a firm stalk. The flower cluster is about 5” long and the plant grows to 7” or 8”. They are long lasting and produce a striking effect when planted in drifts. (April-May)