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Gardening Q & A

Today’s Common Gardening Questions…Answered!

How do I keep my tomatoes from turning black underneath?

Blossom-End Rot (BER) is a common problem for tomatoes in our climate. It happens when conditions prevent the plant from taking up calcium at the time of fruit set (when the flower becomes an immature fruit). If your tomatoes are in the ground, it’s unlikely that you have a calcium deficiency in your soil. The main things that cause BER are uneven watering and low temperatures at fruit set. Let’s look at each of these:

Watering: If you plant in the ground, give your plants a deep soak no more than twice a week. This encourages a deep root system that’s resistant to drought and sudden rains. Using a thick mulch of straw under your plants will also help keep the moisture even. If you plant in containers, make sure your containers are large enough for the plants, and water them every day.

Temperature: The first fruits of the season are usually the ones with BER. This can be from unseasonably cool temperatures, but also from transplanting to the garden too early in the season. We recommend planting Tomatoes outside no earlier than Memorial Day (in Dane County), when the night temperatures are above 50F.

Because BER often corrects itself as the season progresses, look at the bottoms of the fruits on your plants, and remove any that have a brown spot on the bottom. This way your plant can put its energy into growing new, rot-free tomatoes.

How do I get rid of moss in my lawn?

Moss will grow in lawns with any of these conditions: low light, wet soil, and compacted soil. We do carry a granular product called MossMax which will kill the moss you currently have. However, if the conditions that caused the problem aren’t fixed, the moss will grow back. Also know that the moss is not competing with the grass—it has no root system, and it’s too short to shade the grass. The moss is growing because the grass isn’t.

If your grass is growing thin because of shade, you can either get your trees thinned out by a certified Arborist, or you can plant shade-loving perennial ground covers instead. If the soil is compacted or heavy, getting your lawn aerated or spreading an inch layer of compost over the area. If the soil is too wet, you may need to consult a landscape architect to get your yard re-graded to take care of moisture issues. Any which way, after fixing the underlying problem you can re-seed the area so it fills in with healthy grass.

How soon can I plant my ___ ?

First possible planting dates can be divided into two broad categories in our area: cold tolerant plants, and warm season plants. Cold tolerant plants include anything winter hardy, such as perennials, trees, and shrubs; and also cool-season annuals, vegetables, and herbs, such as pansies, broccoli, and parsley. Cold tolerant plants can be planted as soon as the soil is thawed and dried out enough to be workable, which is usually around April 15th.

Warm season plants include many vegetables, herbs, and tropical bulbs. Examples include tomatoes and peppers, basil, and elephant ears. Warm season plants should not be planted until the soil is sufficiently warm, and the night temperatures are above 50 degrees (F). It’s typically safe to put them out around Memorial Day.

I bought a blue Hydrangea a few years ago, but last year the flowers were pink! How can I make them turn blue again?

Some species of Hydrangeas will be either pink or blue depending on the pH of the soil. In our area, Hydrangea macrophylla (Bigleaf Hydrangea), and Hydrangea serrata (Mountain Hydrangea) are the species that will do this. These will include the Endless Summer®, Twist-and-Shout, Bloomstruck, Paris, and Mars varieties.

Because most of us have alkaline soils, the Hydrangea flowers will turn pink. To make them turn blue again, add a Soil Acidifier containing sulfur to the soil around the plants in the spring, well ahead of blooming. Lowering the pH allows the plants to take up Aluminum into the flowers, which turns them blue. Continue to apply every two months until August.

Panicle, Annabelle-types, Oakleaf, and Climbing Hydrangea are not affected by pH, so don’t expect them to ever turn blue!

Why isn’t my ____ up yet? Why don’t you have ____ in stock yet?

We carry many perennials and shrubs that are considered “late-emerging”. These include many popular plants that are garden staples, as well as many native prairie plants. While these plants are often quite hardy and easy to grow, they often don’t “wake up” until late May or even June! This causes a lot of confusion at the garden center each spring. People often prematurely assume a plant hasn’t survived the winter, or start looking for a plant too early in the season when the plants still look like a pot of dirt or dead branches.

Plants in this category include Aralia, Balloon Flower, Black-eyed Susan, Blue Mist Shrub, Butterfly Bush, Butterfly Weed, Coreopsis, Culver’s Root, False Indigo, Hardy Hibiscus, Hardy Plumbago, Hydrangea, Joe Pye Weed, Red (or Swamp) Milkweed, Rose of Sharon, Russian Sage, Summersweet, and many ornamental grasses.

I bought potted daffodils/tulips/crocus, what do I do now that they’re finished blooming?

Potted bulbs are a wonderful way of bringing a bit of early spring into your home. The process of bringing bulbs into bloom indoors is called “forcing”.

Many “forced” bulbs can be planted in the garden, where they will bloom in future years. If you want to do this, make sure that you continue to care for the plants after they bloom. Trim down the spent flower stalks, making sure not to damage the leaves. Place the plant in a sunny window, and keep it well watered. Applying a blooming type fertilizer can be helpful to help replenish the bulbs. The foliage may get floppy or faded, but resist the urge to cut it back! When the chance of frost is gone, plant the whole pot in a sunny, well-drained spot in the garden, burying the root ball a couple inches deeper than what it was in the pot. Wait until the foliage has yellowed completely before removing it.

Forced bulbs often skip a year of bloom in order to replenish the bulbs. Some make the transition better than others: Daffodils, Crocus, Grape Hyacinth, and other small bulbs usually do quite well. Tulips and Hyacinths don’t always make the transition and almost always skip a year.

Should I cut my Daffodils/Tulips/etc. down now that they’re done blooming?

Nope! When spring-flowering bulbs are finished blooming, they begin to replenish the bulb so they can bloom again next year. Cutting the leaves off early keeps them from blooming the following spring, and can even kill the plants. Don’t tie up the leaves either, as this keeps them from getting the light they need. Instead, cut the spent flowers off the plants. Wait until the leaves have turned brown and died down before removing them.

If the bulbs are in a place where the foliage is unsightly, consider moving them towards the backs of beds after the leaves have turned yellow. I keep my bulbs in the middles and backs of perennial beds, because the new foliage of the perennials hides the dying bulb leaves.

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