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Tuesday, October 10, 2017

30th Anniversary highlights ornamental grasses trend for low-maintenance gardens

By Gail Hudson, Horticulture Extension Communications Specialist

As summer flowers fade and the leaves turn fall colors in Minnesota, many varieties of ornamental grasses are at their majestic peak and in full flower.  They stand from 3 feet to as much as 12 feet in height (although some are shorter), as vibrant kings of the perennial garden with their jaunty, yet graceful looks. Ornamental grasses have not only become key components in the driving trend toward sustainable and low-maintenance landscapes, but their strong vertical lines offer living sculpture in today’s native gardening mix.

 Mary Meyer, U of M Extension Educator
“Today there’s a real interest in native grasses and using native cultivars in the garden,” said Mary Meyer, the University of Minnesota Extension professor and educator who maintains the only collection of ornamental grasses accredited by the American Public Garden Association in the U.S. “We went from having exotics from the non-natives and huge numbers of Miscanthus [in the collection] to more and more North American native species. And really the grasses that are native in the prairie.”

Tuesday, October 3, 2017

From our Turf blog: November is the time to dormant seed

November dormant seeding helps promote
a healthy lawn next spring.
By Sam Bauer, Turf Extension Educator

The optimal lawn seeding window is mid-August to mid-September. If you missed that time frame, but you still want to seed this fall, my recommendation is to wait until November to seed. This practice is called dormant seeding and is certainly an effective way to introduce new species and/or varieties of turf into your existing lawn.

By far our most popular post on this site has been the one on this topic, so we are re-posting an article originally published on November 1, 2013.

If you are considering dormant seeding, read on to start planning for November: There’s Still Time to Dormant Seed Your Lawn.

Friday, September 29, 2017

Maple tar spot strikes again

M. Grabowski, UMN Extension Educator
Tar spot may look different on different
species of maple. M. Grabowski, UMN

For the second summer in a row, tar spot, a fungal leaf spot disease is showing up in large numbers. Tar spot causes large black raised spots on leaves. Black spots are often shinny and look like wet tar. Although the symptoms of tar spot are most dramatic in the fall, the fungus actually infects the leaves early in spring when wet weather coincides with spore release. The fungus can only infect leaves, and will survive Minnesota’s winter in fallen leaves within leaf spots.

M. Grabowski, UMN Extension
Tar spot is not a serious threat to the health of the tree. The leaf spots may cause leaves to drop a bit early but not early enough to do significant harm. Gardeners interested in reducing problems with tar spot in the following year should rake up leaves and place them in a back yard or municipal compost pile.

Thursday, September 28, 2017

Prepare for boxelder bugs

Jeffrey Hahn, Extension Entomologist

Boxelder bugs are starting to congregate around the outside of buildings. Take action now if you wish to minimize problems with them later, especially if you have had a problem with them in the past. Although boxelder bugs are just a nuisance, they can potentially enter homes in large numbers. People can see them in their homes not only in the fall, but also during the winter and early spring.
Watch out for boxelder bugs trying to get into your home. 
Photo: Jeff Hahn, University of Minnesota Extension

It is not effective to spray the boxelder bugs found in the landscape. Adults have wings and can easily fly onto your property from adjacent areas. It is much more effective to take steps to help prevent boxelder bugs from entering a home to begin with.

There are two basic ways for dealing with boxelder bugs (and other insects, like lady beetles) that try come into your home seeking sheltered areas for the winter: sealing cracks and spaces and timely insecticide sprays. These are steps you can take yourself or hire a professional to do for you.

For more information on boxelder bugs, including control, see Boxelder bugs.

Tuesday, September 26, 2017

Plant hardy bulbs now for early spring pollinators

Honey bee on crocus
By Julie Weisenhorn, Extension Educator - Horticulture

Pollinators need pollen and nectar as early as April in some parts of Minnesota. Hardy spring-blooming bulbs such as scilla, allium, daffodil, fritillaria, and crocus provide this much needed early season nutrition. These bulbs require a cold period in order to flower successfully and therefore must be plant them in fall (September - October) - in other words: right now!

Bee inside a daffodil flower
Bulbs are relatively inexpensive and easy to plant. Bulbs may be purchased locally or ordered from suppliers either through a catalog or online. Most bulbs require warm, sunny locations. Tip: Sun-loving bulbs can be planted underneath deciduous shade trees because they will bloom before the tree leafs out.

Follow planting instructions on the bulb package for depth and site specifications. Make you mark your planting location with a plant label so you remember what you planted next spring. After planting, soak the soil with water. If conditions are dry (little rainfall), soak the soil with water when dry until the soil freezes.  
Bee on Scilla siberica

Read more from Extension about spring flowering hardy bulbs.

Japanese beetles: Aftermath

Jeffrey Hahn, Extension Entomologist

Now that we are safely past the bump in the road called Japanese beetles (JB), it is time to take stock in what happened this year, whether we should be doing anything now, and even what to expect for 2018. Clearly, 2017 was a year of above average numbers of JB. However, this is not the first time we had high numbers of JB in Minnesota and it is unlikely to be the last. So why did we have so many Japanese beetles this year?
Japanese beetles were bad this year.  However, most plants
will survive this damage just fine.  Photo: Jeff Hahn,
University of Minnesota Extension

Although it might appear that JB occur in cycles (like forest tent caterpillars), in fact their numbers are driven by weather. The most important factor influencing their abundance is a lack of soil moisture. JB eggs and newly emerged grubs are very susceptible to dry soils so during years when we experience drought we typically see relatively fewer JB.

This was true about three to five years ago when we had some very dry summers. However starting in about 2014/2015 we started receiving more normal rainfall and JB numbers responded by becoming more numerous.

There has been a lot of concern by residents as to whether JB feeding would kill plants, especially trees.  While JB feeding definitely affects the appearance of plants, as long as (deciduous) trees and shrubs are healthy and mature, they can tolerate severe, even complete, defoliation.  However, if trees and shrubs are severely damaged for several consecutive years, they can sustain more lasting injury.  Maintain normal care for trees and shrubs to keep up their health.  Herbaceous plants are more vulnerable to JB feeding but also are able to tolerate some damage.  Look for most plants to rebound and be fine next spring.

Many residents also wanted to know about treating grubs to reduce the number of JB numbers on a person’s property. While it makes some sense to try to kill the grubs in your lawn so the adults don’t emerge and find your plants, the reality is that treating the grubs has no impact on how many adults you will find on your property next summer. The reason is that adult JB are good fliers and can fly from as far away as several miles.

If you have plants that are attractive to JBs, the adults will find them regardless of whether you treat for grubs or not. Only treat your turf if grubs are found damaging the grass. This is best done in July and August and into early September. By fall, the grubs are getting too large to effectively treat. They are definitely too large to treat the following spring.

So what about next year? We received pretty regular rains in 2017 throughout areas where JB is common. That strongly suggests that if you saw a lot of JB this year, you most likely will see at least similar numbers next summer. Stay tuned!

2017 Flowers for Pollinators: Which annuals attract pollinators?

By Julie Weisenhorn, Extension Educator - Horticulture

Honey bees on Music Box Mix sunflower, one of the annual flowers in this study

Planting for pollinator health is on just about every gardener’s mind these days.

Bumble bee on Envy zinnia
While there is a lot of research on how native plants help pollinators, there’s not much on the interaction of pollinators and annual flowers. Many people want to do their part, but may only have space for annual plantings. There are conflicting references to the value of annual flowers as pollinator-friendly plants. Which annual flowers attract pollinators? We want to find out, so we designed this study to address how home gardeners might help reverse pollinator decline. Pollinators are attracted to such plant features as flower form, color, size, and pattern. We've been counting pollinators that visit selected varieties of annual flowers like Salvia, Zinnia, annual Rudbeckia, sunflowers, marigolds, cosmos, snapdragons, hyssop, etc. Read more: Flowers for Pollinators

Wonder how your own yard and garden measure up when it comes to pollinator-friendly habitat? Take the eight-question survey that asks "How pollinator-friendly is my landscape?" Are you a "Wanna Bee Pollinator Gardener", a "Bee Benefactor" or a "Pollinator Protector"? Find out!

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