With all of the winter injury this year my rhododendrons have lost many leaves. They are recovering now but the new leaves are much higher and reveal more of the woody stems. Is there a way to prune to encourage leaf development in the lower portion of the shrub?

Remove any branches that are winter-killed or damaged. In the spring, judiciously prune back half of the plant by about half their height. Leave the other half of the plant alone to reduce the shock. The following spring, perform the same procedure to the untouched half. You may have to forsake a few blossoms for a season in order to get lush growth established. Plant other perennials around the base to mask the bare branches until it fills in. Make sure your rhododendrons are watered regularly even in the fall so that they go into winter with adequate soil moisture. Also ensure adequate mulch, at least 3 inches deep. Re-evaluate your site conditions. You may need to provide protection from winter wind and sun that cause desiccation. Make sure the soil is well-amended with compost. Rhododendrons are actually light feeders. If the soil is properly enriched, they will get all their nutrients from the soil and will not require a rigorous fertilizing schedule. A healthy plant stands a far better chance against the unpredictability of Michigan winters.

I have an unusual hosta which has been growing for 3 years, and doesn’t look like any other in my yard. It is possibly a new variety. How would I go about getting a patent on it?

Your hosta is still a youngster by hybridizer’s standards. There are well over 1000 cultivars registered with the International Registration Authority for Hosta. Young hostas, whether seedlings or sports, should always be grown for 5 to 7 years to establish whether they are stable and worthwhile. If they are, there are clearly established criteria for naming. The hosta must be clearly distinct from all other hostas, it must be uniform and stable in characteristics, and must remain constant when propagated. Contact the American Hosta Society, Registrar, University of Minnesota Landscape Arboretum, P.O. Box 39, 3675 Arboretum Drive, Chanhassen, Minnesota 55317. They can provide you with additional information, instructions, and the registration form. If you have access to the web, their site is www.hosta.org, complete with the Society’s history, registration forms and how to process, as well as plenty of useful information about raising hostas.

There is an area in my yard where grass will not grow. It is shaded, near a patch of woods, and on a slight slope. It seems like we replant grass every year, and it will not get established. Any suggestions?

Yes. Stop throwing money away on grass! The very first things that should be considered when siting any plant are its cultural requirements, or “location, location, location.” Many people don’t think about the lawn as a mass of plants, all requiring a special situation in order to thrive. So that said, go at your search backwards: “It is shaded, near a patch of woods, and on a slight slope.” What would work there? The combination of the slope and the tree roots likely also makes the area dry. Under those conditions, you may want to try Epimediums or Geranium macrorrhizum (bigroot geranium). If it’s not real dry, there’s a whole world of shade plants to play with.

I am interested in growing strawberries. What soil, sun, and conditions are best for them? J.M.

Strawberries, like most fruits and vegetables, require full sun. The soil should drain well, as excess surface moisture will encourage mold on the berries. The soil also should have a very rich level of organic matter. Locate strawberries in an area that will warm up quickly in the spring. It also should freeze in the winter, since strawberries need an extended period of cold to produce fruit. Parts of the country where there are not freezing temperatures, such as California, grow strawberries as annuals, importing them from areas such as Michigan after they have had their requirement of cold.

Last year, I moved some wild purple irises from a shady area to a sunny area. At that time, they bloomed in late May. This year, they had no buds on them at all by May 18. Is there a chance they will bloom this year, or ever? Any recommendations?

It sounds like you moved some blue flag (Iris versicolor). Blue flag will tolerate full sun to light shade, but prefers wet meadows, stream banks and marshes. This has not been a warm spring, as in past years. Their time to bloom is late spring to mid-summer, so give them time. However, make sure there is sufficient moisture in their new location and that you have not transplanted the rhizomes too deep. As with all irises, placing the root systems horizontally just below the soil surface is best. It may take another year before they acclimate to the move and their new site before they establish and bloom.

My brother-in-law has many oak trees in his front yard and every fall he rakes up the leaves. I told him to just mulch them in (the soil is quite sandy) as they will help improve the soil. He said that would make the soil too acid. Will this dramatically raise the soil acidity? What if he composted all the leaves; would the compost be too acid to use as well?

Actually, your brother-in-law has a gold mine. Oak leaves in particular are very good for garden soil as they contain micronutrients drawn from the depths of the earth. The best way to add them into the garden is to rake them into a shredder or run over them with a power mower. The oak leaf needs to be broken up in order to release its nutrients. Then they can be tilled into the garden bed using a garden fork. If left intact, oak leaves mat together and promote unhealthy bacteria, which can be transmitted to planted material. Once shredded, they can be worked into the sandy soil, offering an excellent organic amendment to a soil that drains too quickly. It will not dramatically raise the soil acidity. The leaves can be composted but again, must be shredded or chopped up to effectively decompose. If mixed in with ongoing compost, they will degrade much faster and more thoroughly.

I planted a butterfly bush late last summer and it did very well. Early this summer new foliage appeared at the base but no new growth occurred on the branches. Am I supposed to cut the dead branches back to the ground or leave them alone?

One of the greatest treasures for providing life in the garden is the butterfly bush. Hummingbirds and beneficial insects, as well as butterflies, are seduced by the nectar-rich flowers of these bushes. Most plants offered are of the species Buddleia davidii. These large, hardy shrubs (even the dwarf shrubs can reach 8 to 15 feet) are highly ornamental, extremely carefree and very vigorous growers. Buddleias remain evergreen in winters where the temperature does not drop below 20 degrees. Where winters are more severe they can be deciduous, merely dropping leaves, or herbaceous, freezing completely back to ground level. Phenomenal growth is achieved in one season even if they do freeze all the way to the ground. The normal life cycle of this bush is to go dormant in zones 5 and 6. At this point the canes above ground are dead. In early spring, after any danger of hard frosts, they can then be pruned to the ground or you can shorten the main stems to a low framework of 6 to 18 inches. If you are in a marginal zone 5 area, it is a good idea to apply a 3- to 6-inch layer of mulch covering the crown. Since it self-seeds prolifically, it’s best to remove spent flower heads promptly. This results in a second flush of flowers in late summer. No landscape should be without at least one butterfly bush!

I am trying to hide my air conditioner unit. What plants can I place around the unit that will not harm it, nor the unit harm the plants?

That all depends on the air conditioner’s location. If there were a large planting area, you would be better served to distract the eye from the unit with a mixed planting of woody ornamentals and tall grasses, as opposed to drawing attention to it with the ubiquitous soldier course of evergreen shrubs. Always allow a constant 3- to 4-foot minimum clearance around the unit for the inevitable maintenance and for proper airflow. Now, if extra space is at a minimum, such as your condenser being adjacent to the patio, it would be better to have a screen, such as vented fence sections surrounding the visible sides. Dry-set the posts so the sections can be removed for servicing. If done well, it would add an attractive privacy screen effect as opposed to a cover-up.

Is it okay to add old, stale bread to the compost pile? What about tree stumps – can they be buried in the pile to speed their decay?

No, bread should not be added to a compost pile. As far as tree stumps, I wouldn’t add them to the compost pile. They will eventually decay in a long, long time, but in the meantime you will upset the balance in your pile and you won’t be able to turn it to speed the decomposing process. A balanced pile needs both green and brown materials. I would chop it up and use it for a nice bonfire, or maybe rent or borrow a chipper and use the chips around your garden, with maybe a small portion of the chips added to the pile.

This spring I had grass sprout up all over my garden beds. Last fall I put down a 1-inch top dressing of my own compost, which was about a year old at the time. I have been doing this for several years and never had any grass grow in the beds. Is it from my compost or something else? Are there any reasonable methods to prevent it from happening again?

It is most likely not from your compost. Grasses propagate through the growth of tillers and rhizomes. The tillers look like blades of grass that grow along the surface and send down roots where they contact bare soil. In working your garden, you are taking the tillers out in your normal cultivation. Rhizomes grow laterally from the grass, underground. They then send up shoots at points along their length. Often, if you were to pull up a three- to five-inch tall shoot, you may find two feet or more of root. This root is the rhizome. Over time, rhizomes will work their way under or through most bed edging. Pulling up the shoot and as much of the root as possible is the best way to fight back. Using the types of chemicals that would be needed to kill back the grass could harm other plants in the bed, so a chemical solution would not be a good choice.