How late can I plant tulips and daffodils?

These bulbs, along with other spring flowering minor bulbs can be planted until the soil freezes. Be sure to, add a generous (2-3") layer of shredded bark mulch, straw, or evergreen boughs immediately after planting.

What should I do with my Rhododendrons, Holly, and other broadleafed evergreens to protect them for the winter?

First, treat the soil with soil sulfur, or iron sulfate. Mulch the entire area under the branches with one to two inches of peat moss, then shredded bark mulch. The foliage should be sprayed with an anti-dessicant such as WILT-PRUF, when the temperatures remain above freezing for 24 hours. If the plant is in a very exposed area you might consider wrapping the plant in two layers of burlap. Make a cone shape to help shed snow. This should be done by mid-November.

Should I cover ground covers like Pachysandra or Vinca minor?

Yes, since we often have cold, windy weather before there is sufficient snow cover, mulch is needed to protect these broadleafed ground covers. A thin layer of evergreen boughs applied in mid-November will provide good cover. This covering must be removed before growth begins in spring.

When should I buy my Christmas tree and what should I do with it until I set it up?

Since there is more sap in a tree cut before the cold weather sets in, it is advisable to purchase your tree by the end of November and place it in the coolest spot possible. You can cut off an inch of the trunk and set the tree in water, but if it freezes you will have to thaw the water inside. Store the tree in an unheated garage, or covered with cloth on the north side of a building.

Can I save my patio plants such as Hibiscus, Oleander, or Bouganvillas?

You can, but you must have a very sunny and cool area (50-65 degrees). In low light or high temperatures, the plants will stretch for the light, and pest populations will explode, especially spider mites, aphids, and scale. Check weekly for pests and be prepared to spray periodically.

What can I do now to help reduce leaf drop on my flowering crabs next season?

The disease that causes premature leaf drop on some flowering crabs is a fungus called apple scab. The spores over winter on the old leaves which fell during the summer and fall. Raking and disposing of these leaves may help reduce the severity next spring, but since the spores blow long distances, it is impossible to eliminate this problem through sanitation alone. In early spring, when the temperature remains above freezing for 24 hours, spray the trees and soil around them with DORMANT OIL spray. If apple scab has been a recurring and severe problem on your tree, you might consider replacing your crab with a newer more resistant variety.

When should I prune my trees and shrubs?

Most major pruning on deciduous plants (plants that loose their leaves in fall) should be done when the plant is dormant.  During the growing season, a plant’s leaves contain food, in the form of sugars.  Removing these leaves, before they are able to send this food back down to the plants roots in fall, will rob the plant of essential food and stunt it’s growth.  Since the winter weather in Wisconsin can be very cold and dry, major pruning should be delayed until after the coldest part of the winter has past, usually after the end of February.  At this time of the year the plants sap is still down in the roots, but the growing and healing season is just around the corner.

During the dormant season, many shrubs can be heavily sheared or renewal pruned, if needed.  The exception to this practice is spring flowering trees or shrubs, such as Magnolias, Forsythia, Lilacs and the like.  These plants have formed their flower buds during the previous summer, and pruning them in the winter, though it can be done, would remove those buds.  Summer and fall blooming trees and shrubs, however, can be pruned heavily during the dormant season, because their flower buds have not yet formed.

When a deciduous plant has been neglected for a long time, and there are more old declining stems then young ones, it is a candidate for a process called renewal pruning.  This method of pruning involves removing as many as 1/3 of the heaviest canes of the plant, down to the base.  This action will trigger new growth to start from the bottom of the plant.  This process is repeated every year for 3-4 years, until the entire plant has been “renewed”. 

Depending on the variety, evergreens are best pruned in spring after the danger of winter burn is past. Japanese yews and junipers can be pruned twice during the season.  The first pruning, in spring, can be severe if needed, taking larger branches back into the mass of the plant.  This spring pruning is also a good time to remove any winter damaged branches.  The last trimming on these species should be no later then mid to late July so that these new wounds have adequate time to heal before winter. 

Spruce and pine usually do not need to be pruned.  If you do feel it necessary to control their size or shape, they need to be pruned when it is in what is called the “candle stage”.  The candle is the soft new growth emerging from the cluster of buds at each branch tip.  When the candle has finished elongating and is just beginning to harden, up to two-thirds can be cut or pinched off.  This will help control growth and encourage thickness in the plant.