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Why don't my hydrangeas bloom?

Like most shrubs that bloom in the spring or early summer, hydrangeas bloom on buds that formed the year before or on old wood. In other words, the 2004 blooms will come from buds that have already formed or are now forming. These buds are on the tips of the current growth. There are a few exceptions, but they are definitely exceptions and are few.

So here comes my list of five reasons why hydrangeas do not bloom. They are listed in order of importance as gleaned from recent conversations.

First is improper pruning. Any pruning in the fall winter, or spring that removes branch tips will remove flowers. Prune hydrangeas immediately after flowering. In the summer, I prefer to remove entire stems to let new stems grow from the ground.

Second is winter injury. We are approaching the northern limits for successful hydrangea growing. Locate so that they have protection from the winter wind. Also hope that the winter is not abnormally cold. If you lose as little as four to six inches of the tips your flowers will be gone.

Third, hydrangea buds can be destroyed if we have an unusually warm stretch in early spring that starts bud growth followed by a sharp frost.

Fourth would be environmental stresses. Locate the plants where they receive dappled shade or morning sun. Dappled shade is my favorite. That's when you can lay under a tree and still see some spots of sunlight on your body.

Hydrangeas also require a bit more moisture than most shrubs to be happy. Afternoon sun suggests to me a drier and windier site. Deep shade will also limit bloom on most varieties. Also try to observe the frosty spots on your property and avoid them.

I would not be surprised if some of the problems in 2003 came from the 2002 drought and the colder 2002-2003 winter.

Fifth, flowers will not form on any plant until it has matured and is past the period of juvenile growth. With a hydrangea this should not take more than a year or so. Excess love in the form of fertilizer and water can extend the juvenile period.

If you are fortunate enough to get one of those hydrangeas that are forced for Easter enjoy it and then throw it away. I would guess that some of them may be root hardy but I'm almost positive that they will never be bud hardy and bloom in the garden.

If that doesn't suggest an answer to the question, then I'm stumped just like you.

In a recent stretch, over half the questions I received came from people trying to unravel the mysteries of hydrangeas. Although there is a lot that I don't know, researching, and thinking about those questions emboldened me to tackle hydrangeas in an article.

On second thought, that can't be done. Glancing at two catalogs I frequently use, I see that one lists 35 different hydrangeas and the other has 71.

To add to the confusion, those numbers cover as many as five species of hydrangeas all with different looks and/or different habits. Also in play is that usually some of the florets are sterile and some are fertile. So here comes a two-week effort.

To unravel the species confusion, let's start with our native hydrangea, Hydrangea arborescens. There are several cultivars, with Annabelle the most common. If you need to push a hydrangea into a lot of shade, this is the answer.

It gets a large snowball flower that starts green and gradually turns pure white. A disappointed owner recently described its early bloom stages as a hydrangea whose flowers never open. While not the showiest, it has its place in the shady landscape. I like it and find it interesting. The other hydrangeas want no more than dappled shade.

The second species is the one we usually envision when we think about hydrangeas. That one is big leafed hydrangeas or using the Latin is Hydrangea macrophylla. This one includes the common lacecap and mophead forms. Again we get a balance of fertile and sterile florets. The showy ones are sterile and the ones that appear unopened or underdeveloped are fertile.

Recently I am seeing another species, called Hydrangea serrata. This one appears quite similar to the mycrophylla in bloom but with possibly smaller leaves and a bit of color in the leaves both in the fall and the growing season. I've only seen one or two cultivars of this one to date.

When I was about five, I remember climbing a giant snowball tree that grandmother had planted by the front porch. In reality I guess 10 to 15 feet isn't a giant to an adult. It was one of the Hydrangea paniculatas. This group sports large oblong white flowers that fade to pink and then to light tan. They can be trained to be a large multi-stemmed shrub or a small tree.

To many people the most desirable hydrangea is the oakleaf or Hydrangea quercifolia. You guessed- it the leaves look like large oak leaves. The flowers again are oblong and have the same color sequence as the paniculatas.

This one stands out because it has multi-season interest. You start with the spring foliage, and then the bloom, followed by good purple fall foliage, and bark that is cinnamon-colored and very hairy when young and exfoliates as it ages. This is one of my favorite shrubs for four-season interest.

That runs the gamut of common possibilities if we allow for a multitude of cultivars in each group and extensive hybridization. Also, there has been a rash of recent introductions from the mountains of eastern Asia in an effort to increase hardiness. We will continue next week with culture and growing tips to avoid some frequently encountered problems.

There was a time when I was pleased with the great bio-diversity in my yard. My lawn was a wonderful mix of grass, weeds and white clover. Now about the only thing I can find is crab or fall grass or whatever it is. For the rest of the article I'll call it crab grass since I don't want to develop a first name friendship with it.

Judging from several recent conversations, I have lots of company. Why this year and what can be done?

Conversations with a yard chemical salesman proved enlightening. When asked if there was anything that could be done now he said yes with a great bit of hedging. Chemical control now is possible, but when he suggested that I wait for a good frost, I got the feeling it wouldn't be too effective.

In my own yard, since it has never been sprayed I know what happened. We had a wonderful year for seed germination and plenty of weekly moisture for lush growth. Obviously I had plenty of seeds waiting from recent years.

It is also quite possible that one might have sprayed and still been rewarded with vast patches of crab grass. The salesman suggested that when the first warm days arrive in the spring, many people rush for the crab grass control. That's too early, especially in a cool, damp spring like we had this year.

His rule of thumb for crabgrass control is to wait until the neighborhood is yellow with forsythias. There are a number of possible control materials, including some that contain fertilizer.

From the organic gardeners, the solution is to spread corn gluten to inhibit seed germination. There is no question that practices derived from using parts of the cereal grains will reduce weed germination. I've used them. That's one reason to plant cover crops in the vegetable garden each fall. I have not talked to anyone who tried this organic approach in his or her lawn.

Please note that I am not the person to suggest specific products. Contact the Penn State Extension Service at 394-6851 or find a replicable dealer who can answer your specific questions. Remember, chemicals can be used as tools or they can be weapons in careless uninformed hands.

This is one instance where I might consider using a professional. They are licensed in the use of chemicals and have access to materials that the home gardener doesn't. They also have the equipment and the experience to do the job effectively and safely.

Will I break my tradition and treat my yard? I don't know. After all lawn is just that empty area between flowerbeds but I'm quite disgusted with crab grass right now.

As August disappears it is hard to mask the thought that fall is just around the corner. With reluctance or joy, our thoughts turn to one of the staples of the fall garden, the hardy garden mum.

For a few, the garden mum is a great perennial. For the majority, our survival rates and plant response in subsequent years is often a disappointment. I suspect that some of the blame goes to the breeders and the newer varieties. Perhaps the emphasis is put on branching and bloom count, and garden performance is forgotten. I have had real good success with the older varieties.

Unfortunately, I am in the majority. Yet I will offer a check list, gleaned from university sources, that may help.

To establish:

1. Plant early. A green plant or one in bud is easier to establish than one in full bloom.

2. Water often until established in the landscape.

3. Plant in well drained soil. Wet soils are deadly.

4. Cut back as the blooms fade to force new growth and root development.

If they survive the first winter:

1. Make double your regular fertilizer applications on garden mums. Reduce as buds show color.

2. Prune each year after four to six inches of regrowth. Prune resulting branches again to three or four leaves. Complete pruning by July 4.

3. Watch out for aphids and spider mites. Insecticidal soap helps.

4. Divide often. Older plants will die from the center outward.

In the last several years a new type of mum has been introduced. Called Belgium mums, they are more compact with a host of flowers that may be a wee bit smaller. I liked the looks of them and planted about 30 in my garden.

My over-wintering success was about as poor as usual. Of course it was a wet, cold winter and I didn't follow all the rules above. But then I doubt if many of you will either. Even as an annual there is a place for mums in my garden. >

Today we will ramble through a bit of Latin naming while we give some practical information about several wonderful plants. What is a hibiscus?

I can quickly think of three distinct but related shrubby plants with saucer shaped flowers. One is a tropical used as a houseplant. The other two have been focal points in my August garden.

In the name game, hibiscus is the plant genus. If I move up a step on the naming ladder I come to the Malvaceae family which adds plants with similar flowers like hollyhocks and malvas. Moving down the ladder we get more specific as we add the species name.

Many plants have been found in the wild or are selections of plants found in the wild. If an x appears in the Latin name it is hybrid created in a controlled breeding program. We get many new plants as random seedlings or mutations on existing plants.

The taller of the two plants in my garden is Hibiscus syriacus. Most of us will know it as Rose of Sharon. This is a relic from grandmother's garden that is experiencing a rebirth,

It is a stiff upright multi-stemmed shrub, which blooms from late July into September. It can also be a trained standard. That's when you keep only one stem to make a shrub look like a small tree. Watching both forms, I believe you get more flower power from the free growing form. Besides, it is a lot easier.

Colors include white, reddish pinks, purples and even a near blue. In the plant world, as you know, most blues look a bit purple. So does this one. Some have a dark eye in the center of the flower. Flowers can be single, double or somewhere in between.

According to the literature, late winter pruning will increase growth and flowering. My head high plants are only three years old and have not seen the pruners yet.

The other hibiscus in my garden is the die-back shrub with the near dinner plate sized flowers. With this one there is a large number of species and hybrids. Colors favor red, pink and white.

You can find varieties that will be waist high and others that will grow past your head. They do this quickly, as they are very late to emerge in the spring. I don't stake the tall ones but occasionally will pinch when they are a foot or two tall to encourage branching.

As I said, this one is a die-back shrub. I always leave the dead stems as a marker until the new growth appears. This year with the cool spring they were still emerging in early June. Yet by August 1 they were waist to head high and in bloom.

Several days ago I saw someone trying to buy the bluish Rose of Sharon. To him they looked right but he was troubled that they were called hibiscus. That's the reason for the Latin, as confusing as it may seem. Common names often are a path to even greater confusion.