Yard & Garden Line News
Volume 7 Number 12                                                               August 1, 2005
Features this issue:

Small Shrubs
Little Brown Weevils
Stable Flies
Denizens of Detritus
August Garden Calendar
Editorial Notes

Small Shrubs
by Nancy Rose, Regional Extension Educator - Horticulture

Stephandra incisa 'Crispa' Photo credit:
Nancy Rose
'Nearly Wild' rose and Asiatic lilies. Photo credit:
Nancy Rose
Gardeners beware: those blooming shrubs in small one- or two-gallon pots should have this label stuck on the pot - "WARNING: this cute little shrub may soon grow significantly larger than it now appears!". A forsythia (Forsythia sp.), red-stemmed dogwood (Cornus stolonifera), or lilac (Syringa sp.) in a small pot may be only a few feet tall when you buy it, but before you plant it under your picture window, consider the plant's expected mature size. And consider, also, that fast-growing shrubs may reach their mature height within just a few years.

Large-growing shrubs planted in the wrong place can block windows, crowd sidewalks and doorways, and quickly outgrow allotted space. Fortunately, there are dozens of excellent shrubs available that top out at 4 feet tall or less, making them ideal for many landscape situations. Foundation plantings are certainly one good use for small shrubs, but don't limit these useful shrubs to that traditional fringe along the front of the house.

Some small shrubs are special enough to be featured singly (some dwarf conifers, for example) but most small shrubs look best planted in multiples. When planted in groups, small shrubs can serve as a tall groundcover, or create a smooth transition between low-growing turf areas and taller shrubs and trees. Small shrubs that tend to spread by suckering and rooting along the stems are ideal for planting on slopes or steep banks: 'Gro-Low' fragrant sumac (Rhus aromatica 'Gro-Low'), cutleaf stephanandra (Stephanandra incisa 'Crispa'), and the shade tolerant natives dwarf bush honeysuckle (Diervilla lonicera) and red coralberry (Symphoricarpos orbiculatus) are good choices.

Small shrubs can also make great hedges, either formal (like sheared Korean littleaf boxwood, Buxus microphylla var. koreana) or informal (for example, dwarf Meyer lilac, Syringa meyeri 'Palibin'). These shrubs are too short to provide privacy screening, but low hedges are wonderful for guiding the eye through the landscape, defining areas within a landscape, or softening hard lines such as patio or driveway edges.

Perhaps one of the most creative but least practiced ways of using small shrubs is in combination with herbaceous perennials. These mixed beds or borders are a standard feature in many famous English gardens, and there are plenty of ways to mix it up in your own slightly-less-famous garden. The ornamental features available in small shrubs -- flowers, colored or variegated foliage, colorful fruit and fall foliage -- can beautifully complement the blossoms and foliage of blooming perennials and ornamental grasses.

As just one example, pair the subtle leaf-margin variegation of 'Carol Mackie' daphne with the elegant pinstripes of variegated feather reed grass (Calamagrostis x acutiflora 'Overdam'), then mix in red-flowered cultivars of peony, daylily, and hardy chrysanthemum for a long season of bright accents. Add a 'Red Sprite' winterberry (Ilex verticillata 'Red Sprite') to carry the red theme into the winter. Such combinations of small shrubs and perennials provide many opportunities for multi-season interest in the garden.

'Red Sprite' winterberry Photo credit:
Nancy Rose
Selecting appropriately sized shrubs for your yard and garden does require some research. With several groups of shrubs (e.g. potentillas and summer-blooming spireas) you can select any cultivar in the group and be confident that it will fit in the "under 4 feet" range. But with many other shrub species there may be a wide range of sizes within the many named cultivars. For example, most mockorange cultivars reach a lanky 6 feet or more, but the compact cultivar 'Miniature Snowflake' grows only about 3 feet tall. The size range in conifers can be even more dramatic; Norway spruce (Picea abies) is a towering tree up to 80 feet tall, but the species has spawned many dwarf cultivars such as 3' tall bird's nest spruce (Picea abies 'Nidiformis') and the even smaller 1' tall 'Little Gem'. When shopping for small shrubs, check for labels and use reliable reference books to find out about specific cultivars.

Don't judge potentillas just by the straggly specimens seen at gas stations and fast food drive-throughs. Potentillas are tough plants, surviving the poor soil conditions and drought at those less-than-ideal growing sites, but they can be much better looking plants in the home landscape. Rejuvenate these prolific yellow, white, orange, or pink-flowered bloomers in early spring by either cutting back all stems to the ground or selectively thinning out about one third of the stems each year -- you'll be pleasantly surprised by how much this improves their appearance.

Potentilla fruticosa, salvia and cedar.
Photo credit:
Nancy Rose
"Summer-blooming spireas" describes several types of spirea, but the main group is Japanese spirea and its numerous cultivars (Spiraea japonica) [A nomenclatural note: most taxonomists now lump S. ×bumalda and S. albiflora in with S. japonica]. These spireas bear pink or rose-colored flower clusters in early to mid-summer and several cultivars have colorful red-bronze new growth and/or golden foliage. Birchleaf spirea, Korean spirea, and Japanese white spirea are also summer bloomers but they sport white flowers. Many of the summer-blooming spireas also develop yellow, bronze, orange, or red fall color. If you prefer the frothy white flowers of spring-blooming spireas but don't have room for the full-sized varieties, try the romantically named 'Fairy Queen' or 'Swan Lake', both topping out at 3 to 4 feet.

Whether installing a simple foundation planting or designing an elaborate rock garden, you'll find plenty of just-right sized shrubs to do the job. This year, instead of continuing to fight with that overgrown Pfitzer juniper or misplaced dogwood, consider digging out the old and starting fresh with small shrubs that will stay in their assigned seats. Select a combination of deciduous and evergreen small shrubs with a range of ornamental features, add some perennials, grasses, ground covers, or larger shrubs as appropriate, and you'll be well on your way to a beautiful, low maintenance addition to your landscape. Remember, "Small is beautiful."

A SELECTION OF SMALL SHRUBS

'Gro-Low' fragrant sumac (Rhus aromatica 'Gro-Low')
Bush honeysuckle (Diervilla lonicera)
Red coralberry (Symphoricarpos orbiculatus)
Cutleaf stephanandra (Stephanandra incisa 'Crispa')
Annabelle hydrangea (Hydrangea arborescens 'Annabelle')
'Miniature Snowflake' mockorange (Philadelphus 'Miniature Snowflake')
Dwarf red-tipped dogwood (Cornus pumila)
'Red Sprite' winterberry (Ilex verticillata 'Red Sprite')
'Carol Mackie' daphne (Daphne x burkwoodii 'Carol Mackie')
Hybrid blueberries (Vaccinium) - 'Northcountry', 'Northblue', 'Northsky','Chippewa'
Korean littleleaf boxwood (Buxus microphylla var. koreana), cv. 'Wintergreen'
Japanese barberry (Berberis thunbergii ) 'Crimson Pygmy', 'Concorde', Burgundy Carousel, 'Aurea', 'Gold Nugget', 'Rose Glow', 'Sparkle'
Weigela (Weigela sp.) 'Tango', 'Minuet'
Hardy shrub roses (Rosa cvs.) smaller cultivars include 'The Fairy', 'Nearly Wild', 'Carefree Beauty', 'Carefree Delight', 'Winnipeg Parks', 'Chuckles', 'Dwarf Pavement'
Potentilla (Potentilla fruticosa) - 'Little Gem', 'Katherine Dykes', Dakota Sunspot, 'Goldfinger', 'Abottswood', 'Pink Beauty', 'McKay's White', 'Mango Tango'

Summer-blooming spireas:

Japanese spirea (Spiraea japonica) 'Anthony Waterer', 'Neon Flash', 'Little Princess', 'Goldmound', 'Goldflame', 'Magic Carpet' Birchleaf spirea (Spiraea betulifolia) 'Tor'
Korean (or Fritsch) spirea (Spiraea fritschiana)
Japanese white spirea (Spiraea japonica 'Albiflora')
Spring-blooming spireas:
'Fairy Queen' and 'Swan Lake' (Spiraea trilobata cvs.)
Nippon spirea (Spiraea nipponica) 'Snowmound', 'Halward's Silver'

Conifers:

Dwarf globe arborvitae (Thuja occidentalis cvs.) 'Hetz Midget', 'Little Gem', 'Danica'
Globe blue spruce (Picea pungens 'Glauca Globosa')
dwarf forms of Norway spruce (Picea abies cvs.) 'Nidiformis', 'Pumila', 'Little Gem'
Dwarf falsecypress (Chamaecyparis pisifera cvs.) 'Vintage Gold', 'Filifera Aurea Nana'
Dwarf mugo pine (Pinus mugo cvs.) 'Pumilio', 'Mops'

Little Brown Weevils
Jeffrey Hahn, Assist. Extension Entomologist

Barypeithes pellucidus Photo credit:
Jeff Hahn
Some people have found small (1/8th - 3/16th inch long), reddish brown weevils around the outside of their homes in recent weeks. Sometimes these weevils are also found indoors as well. The weevil in question is called Barypeithes pellucidus (it doesn't have a common name).

There isn't much known about the life history of this weevil. It does appear to be associated with trees so homes near wooded areas are more likely to see these insects. The larvae probably feed on roots while the adults are likely to eat leaves. Adults are commonly found during June and July, particularly in eastern Minnesota.

Fortunately this weevil is harmless to people, food and property and is just a nuisance. In this way, it just like a strawberry root weevil. Your best bet is to ignore any weevils you find around the outside of your home and vacuum any you find indoors. The weevils go away on their own by early August.

Stable Flies
Jeffrey Hahn, Assist. Extension Entomologist

Stable fly. Photo credit:
Jeff Hahn
Whether you are outside at your favorite lake cabin or sitting in your backyard in town, you probably have experienced a problem with flies biting at or near your ankles. These flies, similar in appearance to house flies, are known as stable flies. Stable flies, sometimes called biting house flies or ankle-biters, are about 1/4 - 3/8th and are gray with four longitudinal black stripes on their thorax.

However, while house flies have sponging mouthparts for sopping up liquid food, the mouthparts of stable flies are modified into a long, sharp bayonet-like proboscis. They feed on the blood of not only people but on many other mammals, including dogs, cattle, and horses. They are very persistent and very annoying.

The larvae develop in moist, decaying organic matter, such as urine-soaked straw and other soiled animal bedding, decaying grass clippings, poorly managed compost piles, or other decaying vegetation, preferring sites that are loose and not compact. However, you would not expect to find them in fresh manure. It takes the larvae about nine days to develop before they pupate. The adults appearing about two weeks later. Stable flies are active throughout the summer and into the fall.

Unfortunately stable flies are very difficult to control. Repellents, e.g. DEET, and protective clothes are partially effective in controlling stable flies. Sanitation of potential breeding areas can help but stable flies are strong fliers and can invade your yard from outside your property. If dogs that are outside are sufficiently bothered, protect them by placing them inside a screened kennel.

Get the low down on this month's insect pests at Insects http://www.extension.umn.edu/projects/yardandgarden/EntWeb/Ent.htm

Denizens of Detritus
Janna Beckerman, Extension Plant Pathologist

Bird's nest fungi in mulch
Photo credit:
Janna Beckerman
As more and more people learn the value of mulching their plants, many are discovering that mulch not only reduces weeding and maintains moisture, but introduces some really cool fungi-the bird's nest fungi.

Several species of bird's nest fungi occur in North America, but the most common, as the name suggests, is Crucibulum vulgare (vulgare is Latin for common). Careful examination of your wood chips may reveal these small (about the size of a tack), elaborate fruiting bodies that look like (drum roll, please) little bird's nests!

Bird's nest fungi are saprophytes that decay wood, bark, and mulch, and do not harm plants. As their name suggests, the small bird's nests are filled with "eggs" that are small envelopes containing spores. The "eggs" (called peridioles) are often bean-shaped, and range in color from white, grey, dark brown or shiny black eggs reside in is a splash cup (the nest), which catches raindrops. The force of splashing rain propels the "eggs" out of the cup, and several feet away. Some species of bird's nest fungi have envelopes that stick to substrate by a coiled spring with a sticky end called a funicular cord. When the envelope is splashed out of the cup, the coil snaps and extends a microscopic tail that catches on any blade of grass, stem, or twig. The coil then wraps around the substrate like a tetherball, where it remains. By flinging its "egg" high above, the fungus all but guarantees better spread of the enveloped spores when the peridiole breaks down. A separate group of bird's nest fungi, the Mycocalia, Nidularia and Nidula have sticky peridioles that directly attach to substrates without a tether.

Bird's nest fungi regularly appear in the fall, but be can be found almost anytime where there is wood chip mulch. As bird's nest fungi do not damage living plants, control of these fungi is not necessary. Occasionally, bird's nest, or the closely related "artillery fungi" can be a nuisance if the "eggs" stick to the siding of houses or cars. Should bird's nest fungi become a nuisance, removal of the mulch, coupled with decreasing irrigation can minimize the productions of "nests." As these fungi are a curiousity and not a problem, fungicides are not recommended for treatment of bird's nest fungi.

For more information: http://www.anbg.gov.au/fungi/birds-nest-cannonball.html
http://www.extension.umn.edu/projects/yardandgarden/ygbriefs/p321birdsnests-etc.html

For pictures: http://www.mykoweb.com/CAF/skey/birdnest.html

Please check out the diagnostics web pages at
http://www.extension.umn.edu/projects/yardandgarden/diagnostics/

August Garden Calendar
Compiled from conversations with Bob Mugaas, Nancy Rose, Patrick Weicherding, Regional Extension Educators

Lacecap flower of hydrangea. Photo credit:
Beth Jarvis
Lawns:

Water as needed. If temps soar back into the 90s–-an inch of water every week to 10 days, will keep lawns alive. If it's very hot, over 90, for 5 to 7 days, water more frequently. Conditioned turf has gradually become adjusted to growing in dryer conditions.

Some over-seeding and lawn repair can start now. Mid-Aug to Sept. is better.

If there are lots of perennial weeds, you should treat those before starting a sodding or seeding project. If you do it now, you'll be in good shape for seeding later in Aug.

Avoid post-emergence herbicides when it's so hot and grasses are stressed. Broadleaf herbicides can also cause damage when grass is stressed. Non-selective herbicide, such as glyphosate may be used, as long as the grass is actively growing and temperatures are below maximums on the label. Selective removal not advised when under heat and drought stressed.

Lawn fertilizing can wait a bit.

Trees and Shrubs:

Prevent tree stress: now is time when stress is most significant on woody plants. Most woody plants are suffering from lack of water–-drooping, color change, defoliation are all signs of drought stress. The high temperatures cause a lot of evaporation from soil so in spite of "normal" rainfall levels, the soils are extremely dry. Trees should be getting at least and ideally 2 inches of water per week, especially on trees 5 y/o or less.

Keep monitoring for insects and diseases.

Keep weeds in check around trees by mechanically removing or mulch. Refresh mulch to 3" deep as needed.

Continue pruning thinning of shrubs that have flowered this summer. Spring flowering shrubs should have been pruned earlier.

Even though we have passed the primary beetle activity period, it's still not wise to prune oaks until the dormant season. July-September is the 2nd highest period of oak wilt infection.

Promptly repair any storm damage to trees and shrubs.

Fruits, Flowers and Veggies

Daylilies can be divided once they've finished blooming. Seed heads should be removed, regardless whether the daylilies are divided or not. Growing Daylilies

You can prune back raspberry canes that produced fruit this summer. They won't be back.

Try to pull weeds before they've set seed. Weeds with mature seeds should not be tossed in the compost. Compost won't get hot enough to kill the seeds.

Slime mold has been real common this year. Here's the Yard & Garden brief on the topic. http://www.extension.umn.edu/projects/yardandgarden/ygbriefs/p323slimemolds.html

Previous years' check lists:
August 1, 2004:
http://www.extension.umn.edu/yardandgarden/YGLNews/YGLN-Aug0104.html#tips
August 1, 2003:
http://www.extension.umn.edu/yardandgarden/YGLNews/YGLN-Aug0103.html#august

Editorial Notes

Plumeria and friends. Photo credits:
Beth Jarvis
The warm weather we experienced in July made it awfully hard for many of us to work outside, especially if we had only weekends free for gardening. I certainly have a bumper crop of weeds in a few places!

The heat has caused problems for squash and cucumber growers and fanciers of tomatoes and peppers. Heat causes flowers to drop off or not form. I wrote about in 2002 and here's the link: http://www.extension.umn.edu/yardandgarden/YGLNews/YGLN-July1502.html#flowers

Deb Brown has switched days on MPR. She'll be on the first Friday of the month, instead of the first Thursday. (See below for info.)

Julie Weisenhorn will conclude the landscaping project story in a future issue. Carl Rosen will discuss planting garlic in the Sept. 1 issue. We will publish Bob Mugaas' article on the changing face of garden herbicides will appear in the September 15 issue. This is the companion of the lawn herbicide piece. On October 1, Patrick Weicherding will write about on-going research at the U that's evaluating whether butteflying, scoring or teasing apart circling roots in container grown trees makes a difference in the establishment of trees. With the October issue, we return to monthly publication.

Please feel free to cut and paste any of the articles for use in your own newsletters. All we ask is that you give our authors credit.

Back issues Yard & Garden Line News are on the Yard & Garden Line home page at www.extension.umn.edu/yardandgarden/.
Deb Brown answers gardening questions on Minnesota Public Radio's (MPR) "Midmorning" program on the first Friday of every month at 10 a.m. The program is broadcast on KNOW 91.1 FM, and available state-wide on the MPR news radio stations. (Scroll down for map.)

The Yard & Garden Clinic closed December 12, 2003 due to budget cuts. Questions from the general public will no longer be accepted. Samples will not be accepted.

For plant and insect questions, visit http://www.extension.umn.edu/askmg. Thousands of questions have been answered, so try the search option in the black bar at the top left of the board for the fastest answer.

If you would like to receive an e-mail reminder when the next issue of the Yard & Garden Line News is posted to the web, just send an e-mail to: listserv@lists.umn.edu (note: the second E in listserve is omitted), leave the subject line blank, then in the body of the message, type: sub yglnewslist or to unsubscribe, enter: unsub yglnewslist

Happy gardening!

Beth Jarvis
Yard & Garden Line Project Coordinator


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