About 12 years ago I purchased a 1929 English Tudor, which at one time had beautiful rose and perennial gardens. Unfortunately they were left to die out except for invasive star of Bethlehem. This has surrounded the house. In the past three years I have dug up every bed and sifted all the soil. All I did was disrupt them; every little baby developed into healthy adult bulbs. What must I do to rid the beds of these menaces? They come up like weeds every spring.

There’s no sugarcoating this…You do have some work ahead of you. Here are several options, listed in order of effort.

1. Continue to dig them out every spring; this could take years to get rid of them.
2. While a little time consuming, using boiling water is very effective without using chemicals. (Be sure you wear a long-sleeved shirt, closed-toe shoes, and long pants to protect your skin should any of the water splash on you.) If the tubers are several inches under the soil, stir them up enough to get the tubers closer to the surface, and pour the water on them at very close range. Watch for new growth and repeat.
3. If you have not already replanted the area(s), cover them with cardboard (or a thick layer of newspaper) and a heavy layer of mulch for one entire growing season. The cardboard and newspaper can be turned under the following year as compost. Any plant must have light to survive and store food; depriving them of that results in death. But these guys don’t go down easy; some may survive and will require digging out or boiling water. Another option is to cover the area with thick black plastic.
4. Finally, spray with a vegetation killer and wait. Spray any survivors. This means everything dies, including many living organisms that are good for the soil. This type of product also leaches into the soil because the plants don’t usually consume all of it. Be doubly cautious about the quantity used and mindful of any nearby water sources.

Are all hydrangeas perennials? If not, how can you tell which are or which are not?

All hydrangeas are either woody or herbaceous perennials. The problem for northern states like Michigan is that not all hydrangeas are winter hardy, and are not able to take the Zone 5 winters that can dip to -20 degrees. We seem to crave those bigleaf hydrangeas (Hydrangea macrophylla) with lovely pink and blue, large lacecaps. They do not do well in Zone 5 unless extremely well-sited. Once you travel south into Zone 6 and beyond, the plants become more common and successful. In Zone 5, these hydrangeas should be considered container plants to be brought inside for the winter.

There is a climbing hydrangea (H. petiolaris), which is winter hardy here and can be used both as a shrub or a disguise for a large structure. It produces a white blossom in late June that is fragrant and lasts for two weeks or more. Two other hydrangeas with a large shrub or spreading tree habit are panicle hydrangea (H. paniculata) and oakleaf hydrangea (H. quercifolia). Both are winter hardy and work well in a larger landscape. In both cases, it is important to obtain a named variety from a reputable nursery to insure plant characteristics live up to your expectations.

We get dead circles in our grass. Inside the circle, the grass looks fine. We have had the grass replaced, aerated, and seeded, yet the problem keeps returning. How do we fix this?

The symptoms you describe are characteristic of yellow patch (caused by a Rhizoctonia fungus), sometimes known as “frog eye” or “summer patch.” It occurs during hot, dry and windy weather near the end of summer. Drought-stressed, shallow-rooted Kentucky bluegrass lawns are the most susceptible. It often shows up near paving or parts of the lawn that dry out first.

You need to review your lawn maintenance and cultural practices. Overuse of nitrogen fertilizers and excess thatch can make the problem worse. By aerating, you have taken a step to reduce thatch and improve water penetration. Make very sure that your mower blades are sharp, and that the grass is mowed no shorter than 2-1/2 inches. Mowing too short sets the lawn up for weeds and further disease. When you water, water deeply to wet the entire root zone and water consistently. Do not let the turf dry out. Betting on Mother Nature to be cooperative with her rain showers can often make the homeowner the loser in the “turf stakes.” Apply less nitrogen, particularly in midsummer, on Kentucky bluegrass lawns.

If you find you must reseed, select resistant varieties. Studies have also shown that simply adding a small percentage of perennial ryegrass to bluegrass can greatly reduce the problem.