Leaving Spring Flowering Bulb Foliage Strengthens Next Year’s Blooms

 The health of this year's foliage will determine the amount of carbohydrates that will be stored in the bulb below ground this fall. These stored reserves, in turn, determine the strength of the blooms for next spring.

Some gardeners attempt to "tidy up" the foliage by gathering the leaves into bundles and either braiding or tying them in a knot. Although it is better than removing the foliage, the leaves that are inside the bundle will not be exposed to light, reducing photosynthesis and future blooming potential.

As the blooms fade, you should cut the flower stalk off to prevent seed formation, which uses up food reserves that are better spent on bulb growth. However, help the foliage thrive by providing a light application of 5-10-10 fertilizer  and water when the weather is dry. When the bulb foliage begins to turn yellow or brown, you can remove the leaves and add them to your compost pile. Tulip foliage generally dies back by mid-June, but daffodil foliage can remain green until mid-summer.

You can make the bulb foliage less noticeable by interplanting with perennial and annual flowers. Interplanting also will help keep the bed interesting long after the bulb flowers fade. Select plants that bloom at different times in spring and summer to keep the bed in color throughout the season. Plants such as candytuft, false rock-cress, and phlox provide early color yet stay low to the ground so they provide an attractive background for bulb flowers. Plants such as daylilies and coreopsis, as well as many annual flowers, grow a bit taller in late spring and summer, so they can provide a good screen to mask the bulb foliage.

I read in my garden books that now are a good time to prune the coniferous evergreens in my yard.  How should I do this?

Now, when the new growth is soft, is an excellent time to prune chamaecyparis, arborvitae, yew and juniper.  Simply pinch out or cut back terminal growth on the new branches leaving a small portion of the new growth to develop future growth buds.  Pruning will result in thicker, denser foliage and restrain plant size.  Coniferous evergreens used for hedges should be sheared at this time making sure to keep the top of the hedge narrower than the bottom.

June is also the proper time to prune mugho pines in the home landscape.  This is easily done by pinching back the new shoots or “candles.”  Buds for next year’s growth develop on new candles, which grew this year.  Eliminating a percentage of the buds each year will help to keep the plants from becoming over-grown.

We have always been told you can change the color of the flowers on a hydrangea by adjusting the soil pH.  How do we do this?

Color variation in hydrangeas is due to the presence or absence of aluminum compounds in the flowers. If aluminum is present within the plant, the color is blue. If it is present in small quantities, the color is "in between," and if it is absent, the flowers are pink.

Soil pH indirectly affects flower color by affecting the availability of aluminum in the soil. When the soil is acid, aluminum is generally more available to the roots. When the soil is alkaline, the availability of aluminum is decreased and the flowers are pinker.

To gradually change flower color from pink to blue, broadcast 1/2 cup of wettable sulfur per 10 square feet and water it in. To make the flowers pink, broadcast one cup of dolomitic lime per 10 square feet and water it into the soil. It may take a year to see a noticeable change in flower color from this treatment.

Another, quicker way to achieve a change in flower color is through liquid soil drenches. To make the flowers blue, or perhaps more blue during the growing season, dissolve one tablespoon of alum (aluminum sulfate) in a gallon of water and drench the soil around the plant. To make the flowers pink, dissolve one tablespoon of hydrated lime in a gallon of water and drench the soil around the plant. Avoid getting the solution on the leaves because foliar damage may result.

You cannot change the color of white flowered hydrangeas by adjusting the pH.  The above methods only work on those varieties, which produce blue or pink flowers.