After losing my third Pieris japonica in the last 4 years, I’m ready to give up. I thought exposure to wind might be the problem, so I planted the last couple in relatively wind-protected areas, but to no avail. Even though they were all planted in different areas, they all died the same way – turning dry and brown at the top (the lower leaves were still somewhat healthy and green), then the same thing would gradually happen to the lower leaves. Can this plant be grown successfully in this area or should I give up?

Pieris can indeed be successfully grown in our area. As with boxwood, soil and location are the keys. While these plants share the same requirements for planting location, the soil needs of a pieris are much more difficult to properly provide.

Pieris require a much more acidic soil (pH 4.5-6) and they have little tolerance for clay. To be successful, either prepare a raised bed or remove soil and reconstruct the planting area using loose topsoil, sphagnum peat, and pine bark. Once planted, mulch thoroughly with pine bark and most importantly, keep the soil evenly moist, especially during February and March, when most winter damage occurs. Fertilize just like you would any azalea or rhododendron.

Periodically check the pH of the soil (1-2 times per year) and adjust when necessary. Roots fail to develop when the pH rises above the optimal range, at which point decline may begin. Soil tests are very critical when plants are located near foundations or sidewalks where lime may be leached from the masonry, causing the pH to rise.

Once again, the “hardy” mums I planted last fall didn’t make it through the winter. All I have now on each plant is a few straggly stems of foliage – nothing like the dense, bushy plant I had. I have mulched them with 4 inches of shredded bark for the winter, but that has not helped. How can I get these mums to come back?

September is the month to start planning and planting your fall garden. Annuals start their decline and its time to add fresh new color to your flower beds, pots, and even hanging baskets.

As temperatures cool down, colors turn up and intensify. That’s why the ever popular garden mums remain high on every gardener’s want list for fall plantings.

Over the years, mum breeders have provided us with wonderful new colors, sizes and shapes of the ever-popular garden mum. But, as these new characteristics were developed, something else had to go. It takes a lot of energy to produce all those wonderful new qualities that our new mums possess, and therefore, generally, they don’t have enough vigor left to overwinter.

While I do have a compost pile, I wondered if it is OK to use grass clippings and leaves as a mulch. I have heard that they actually remove nutrients from the soil as they decompose and, therefore, shouldn’t be used as a mulch. It seems to me that they would be actually returning nutrients to the soil as they decompose. Please advise.

Organic mulches such as grass clippings do eventually return nitrogen and other nutrients to the soil. However, during the early stages of decomposition, the microorganisms responsible for the breakdown of the mulch require nitrogen and will steal it from the soil. This may cause a temporary nitrogen shortage to surrounding plants unless it has been supplied with nitrogen supplements such as cottonseed meal, bloodmeal, or urea.

If grass clippings are spread too thickly, they will heat up and make a hot, slimy mess. If they are too close to the stems of young, tender plants, this reaction can cause damage. Further, as the layer compresses, it can become tight and allow only anaerobic decomposition, often producing a bad odor in the process.

While some gardeners may disagree, grass clippings are not a preferred mulch. It’s best to compost them completely in a compost pile and use the resulting rich humus to enrich new or existing planting beds.