Ask the gardeners

My vegetable patch slopes down to the north border of my garden. On the property line I laid about 30 feet of concrete blocks to raise the earth level up to 8 inches. Is there anything I can grow in the holes in the blocks. The openings are 4x4 inches and 8 inches deep. Would marigolds be satisfactory? The area gets full sun.

Yes, marigolds would be fine there as would portulaca, if dry conditions will be a problem.

If you can keep the plants watered, then petunias, nasturtiums, salvia, and begonias, either mixed or separately, would be atttractive. Or you could grow herbs, such as parsley, sage, chives, thyme, summer savory, and many others.

We have the same situation and have grown herbs mixed with flowers in the blocks for many years. We use well-rotted manure or compost in the bottom of each hole to act as a blotter. Then we add a mix of equal parts sand, peatmoss, garden loam, and rotted manure.

For most plants you will need to water every other day in very hot weather.

How much shade can an azalea take? Can they stand Chicago winters?

Azaleas do well in semi-shade. Too much shade will cause sparse bloom or none at all.

Most azaleas in the colder parts of the US (which includes Chicago) have their flower buds killed in low winter temperatures, especially during periods of high winds which add to the chill.

In protected areas, some folks have been able to protect their plants with burlap screens around them which then are filled with leaves.

It's best to plant the hardiest kinds, such as Azalea mollis, Pinxterbloom (native or wild pink type), and some of the Ghent hybrids. Your nurseryman probably handles some of the hardy ones.

Potted florist azaleas would not be hardy in your area, but can be rebloomed indoors.

We had a tulip tree given to us five years ago and it now is 15 feet tall. The leaves are lovely but when can we expect to see it bloom? Is there anything we can do to hasten blooming?

Tulip tree, or or Liriodendron, is a magnificent member of the agnolia family and it won't bloom until it's 10 years old or older since the tree reaches maturity at a height of 100 feet or so.

Nothing can be done to the tree or soil to hasten blooming. Is will bloom beautifully as soon as it reaches the proper stage of maturity.

Liriodendron is from the Greek, meaning lily and tree, and alludes to the shape of the flowers. It's worth waiting for.