Ask an MNLA Certified Professional offers you the opportunity to pose questions to green industry experts. Every two weeks specific questions will be selected and posted along with a variety of industry responses.
How logical is it to do home landscaping in the middle of October in Minnesota? -- Scott
There is no problem doing landscaping in mid October. Most all plants will take to transplanting very easily at that time. The only exception would be your evergreen trees and shrubs. For evergreens I recommend planting them by Oct. 15th. and keeping them watered until the ground freezes to avoid winter burn. You can also reduce the risk by spraying an anti-desiccant such as Wilt Pruf on some varieties of evergreens to reduce needle moisture loss during the winter months. This spray must be applied in the fall when temperatures are above 40 degrees. For all other trees, shrubs, and perennials plant now and sit back and enjoy in the spring.
-- Nick Sargent, Sargent's Nursery, MNLA Certified Professional
Landscaping can be done in October in Minnesota. I have found, though, that a higher percentage of plants will fail to survive the winter than for earlier planting dates, especially for evergreens. So you can plant if you wish, but there is a bit more risk. If now is more convenient than next spring, go ahead and try it. Otherwise, I think spring is a little better.
-- Ed Plaster, DCTC, MNLA Certified Professional
There are many landscape projects that can be accomplished in October/November. Most deciduous trees and shrubs can be planted in the fall (exception Evergreens/Birch/Rubrum Maples/Oak should be planted in spring/early summer). One can prepare/clean up annuals/perennials/landscape beds up until early November. Spring bulbs can be planted and mulch can be installed. Existing perennial & rose beds should be mulched after frost has set in the ground about Thanksgiving each year. The vegetable garden should be cleaned up removing all vegetation. Deciduous trees can be pruned in November(exception crab apples/fruit trees best prune in March each year). Pruning of deciduous shrubs should wait until spring (exceptions forsythia/lilacs/rhododendrons/azaleas best pruned after flowering in spring) Existing buckthorn and volunteer trees(mulberry/box elder)should be removed from existing landscape and wooded areas. Treat stumps with Round-up to prevent reoccurrence. The last application of lawn fertilizer (winterize) should be applied by middle of October. As you can see there are a lot of projects you can complete in the fall to get a jump on spring. Go for it!
-- Tom Haugo, Bachman's, Inc., MNLA Certified Professional
October can still be a good time to start your landscape project and as long as the weather is still cooperative. There might be some particular plants that you will have to avoid planting that late in the season but as long as you get water on the plants and incorporate some type of root stimulator you should be fine.
-- Lance Barthel, Greenleaf Nursery, MNLA Certified Professional
Deciduous trees and shrubs can be planted until the ground freezes without any harm to them. Evergreen trees and shrubs should be in the ground by mid-October. Evergreens need to establish a root system so that they can take up enough moisture before the ground freezes. If evergreens do not take up enough water there could be some winter damage like winter burn. We want to make sure that all evergreens are thoroughly watered before the ground freezes to help prevent winter burn.
-- Robin Fruth-Dugstad, RCTC, MNLA Certified Professional
How do I identify Buckthorn in my yard and what can I do to remove it? -- Ann
Buckthorn has a glossy green leave that does not go dormant until late November each year. It is typically the last shrubby tree to lose it's leafs in the fall. When all of the under story leafs in the woods or in
your landscape are dormant, Buckthorn is still green. Buckthorn has
horizontal stripes in the bark and 2-3" thorns in larger tree forms. It is considered enviromentally invasive to our woods and urban landscape. Buckthorn is found in every county in Minnesota. It has black berries that are eaten by the birds. Birds are the carriers of the seeds. When the bird stops to rest, out comes the seeds for the start of a new Buckthorn. Each berry has 4-5 seeds which can grow into 20-30' under story trees. The aggressive nature of Buckthorn can be harmful to our environment and eventually cause established over story trees (oaks/ash/maples) to decline and die. See attached photo's to help you identify Buckthorn (click here for photos: Buckthorn Berries; Buckthorn Bark; Buckthorn Leaves).
Solutions: Remove largeBuckthorn tree(s) with a chain saws and paint/treat stumps with a herbicide such as Round-Up. If the trees are small and the ground is wet (saturated), you may be able to pull them out in loose soil. If you choose not to use chemicals, totally remove the stump (grub out/grind out) or remove all of the tree bark 6" above grade to 3-4" below grade. If Buckthorn is inside an existing hedge, cut off Buckthorn near ground and treat stump with Round-Up. If you cannot remove the Buckthorn, call a reliable tree service to assist you in the removal process. One needs to be vigilant each and every year as one finds Buckthorn in your yard. Good Luck!!!!
-- Tom Haugo, Bachman's, Inc., MNLA Certified Professional
What mulch is best for the shrub bed I am planting? -- Julie
Mulches can be a fine finishing touch to a shrub bed that helps preserve moisture, suppress weeds, and give a finished look to the planting. You can choose inorganic mulches like gravel, or organic materials like wood chips. In recent years an explosion of materials in new colors and textures provide the buyer a wide selection of effects.
For many uses, you may simply choose the mulch that looks best in your landscape and that pleases you the most. For acid-loving plants like azaleas or rhododendrons, I advise avoiding limestone-based rock mulches. Over time, these make the soil less acid and cause problems. Organic mulches insulate soil from winter cold much better than rock mulches, and should be selected for plants whose roots need protection. These include many fine shrubs like many roses and Endless Summer hydrangea. I personally prefer organic mulches like wood chips for their appearance, their insulating qualities, and their contribution of organic matter to the soil.
Please keep in mind that no mulch eliminates the need for care. Some weeds eventually appear and need to be removed, even if a landscape fabric is installed under the mulch. Periodically, dressing the bed with fresh mulch, especially organic mulches, keeps the bed looking good. Bark mulches may need to be topdressed as often as every three years for materials like softwood barks to as long every seven years for decay-resistant materials like cypress chips. Good luck with your planting!
-- Ed Plaster, Dakota County Technical College, MNLA Certfied Professional
In looking at ornamental grasses, what is the difference between a cool season vs. warm season grass? What kind of maintenance will have to be done? -- Jill
Cool Season Grasses - Green up early in spring, produce flowers in late spring or early summer, may be dormant in summer especially in times of drought and resume growth again in fall. (Ex. Feather Reed Grass, Fescue Grass, Saphire Blue Oat Grass)
Warm Season Grasses - Slow to begin growth in the spring, flower in late summer and fall, grow actively in heat or summer conditions and are often drought tolerant. (Ex. Miscanthus var., Panicum var.)
* Ornamental Grasses can be planted in spring, summer or fall. It is a great plant that doesn't need that much attention and has very few insect problems.
* In the fall, plant only container plants with well-established root systems and allow for at least one month of growth before winter.
* Cutting back your ornamental grass 4 to 6" from the ground should be done in early spring so that you can benefit from its great winter appeal. This will promote new plant growth for the following year.
* You can divide your grass plants after a few years time to create more plants or thin out some of the old dead centers.
-- Lance Barthel, Greenleaf Nursery, MNLA Certfied Professional
We found some unusual pumpkins in our garden this year. They have lumps and are a funny color. Can you identify the variety? -- Sandy
The lumps and discoloration on your pumpkins are symptoms of a virus. Most viruses are spread by insect vectors. The best method of control would be to control the insects, but with the cooler temperatures insects are not as active now. If it were earlier in the season I would recommend roguing (pulling) all infected plants immediately, but with the end of the season approaching I would recommend a good fall clean up for the entire garden. Click here to see photo.
-- Robin Fruth-Dugstad, Rochester Community and Technical College, MNLA Certfied Professional
I would like to clean up the mess in my perennial beds so they look neat during the winter. My neighbor says I shouldn't cut back my plants until spring. We live in the northern part of the state. Who's right? -- Audrey
I believe the answer to your question is somewhere between your idea and your neighbors. It's always nice to have the mess cleaned up in the fall, but many times it is better for the plants to have some stems left to catch leaves and snow. The leaves and snow act as insulation for the plants. If you have any tender perennials, zone 4-5, they definitely need the insulation (mulch). The purpose of the mulch layer is to keep your plants from thawing and refreezing and to keep them from sprouting too early in the spring. The mulch should be removed in the spring after danger of frost has passed.
I've included two photos; one of my perennial bed before cleaning up and one after cleaning. Notice that the plants were cleaned up, but there is still plenty left to catch leaves and snow. What is left looks neat and will more than likely be covered by snow in the winter.
Some plants like ornamental grasses Autumn Joy Sedum can be quite attractive in the winter. You may wish to leave those for aesthetic reasons.
-- Sue Jacobson,University of Minnesota , Crookston, MNLA Certfied Professional
*Certified Solutions is aimed at giving you professional information that may assist you with your individual landscape or gardening needs. We try to provide quality information on plants, landscaping and gardening, but make no claims, promises or guarantees about the methods or products suggested.