Non-Blooming Hydrangeas

Weather, pruning may be cause of non-blooming hydrangea

Bill Sevier, Ask a Master Gardener

Saturday, January 28, 2017

Q: I planted some mophead hydrangeas I bought from a local nursery, and they are not blooming. What could cause this? Amy, Tulsa.

A: The short answer is that the non-blooming is most likely related to pruning or weather issues, although there are other causes.

The Tulsa Master Gardeners maintain a helpline at the OSU Extension Office on 15th Street, and this is certainly in the top 10 questions called in during the growing season.

There are 23 different species of hydrangeas and five are cultivated in the U.S. These are smooth, panicle, bigleaf (mophead, lacecap), oakleaf and climbing hydrangeas, and they all share some, but not all, of the flowering habits of your hydrangeas.

In regards to blooming, the mopheads come in two general varieties. The older classic ones that just bloom in spring and the newer remontant (reblooming) varieties that bloom in spring into fall. The spring bloomers form flowers on buds developed during the previous late summer and fall. Pruning these shrubs during fall, winter or early spring will remove the flower buds with a loss of blooms for that season.

Hydrangeas in the reblooming group have last season’s buds as the others do but also form buds in the current summer, which bloom that summer and fall. If these are pruned winter or spring, the spring blooms will be lost, but the plant should still bloom in summer and fall.

Another cause of non-blooming of hydrangeas relates to the weather. Spring-blooming plants whose buds were developed the previous year may lose those buds with a late spring freeze. As it warms in early spring, the flower buds expand with water and begin to soften (bud break). As they do this, they lose their cold tolerance and a late freeze may kill them. The reblooming hydrangeas also may lose their spring flowers with a late freeze but will still bloom later in the summer. That is why this type of hydrangea is popular in the northern states.

These are the main causes of hydrangeas not blooming, but there are others.

Most varieties need about four hours of sun to bloom. If a hydrangea is planted in full or mostly shade, it will have nice green leaves, grow tall but not bloom.

Another factor to consider is that these plants need time to develop root systems and develop height before they consider blooming. Some plants may take two or more years to do this, so if everything else seems optimal and the plant doesn’t bloom, give it more time.

A last possible cause relates to most all plants in the flower or vegetable garden. If you use too much nitrogen fertilizer, plants will grow tall and green and not flower.

For a helpful review of hydrangeas and their problems, the Proven Winner website is worth reading.

Garden tips

•        Begin planting blackberries, raspberries, strawberries, grapes, asparagus and other perennial garden crops in February.

•        One can continue in the month of February spot-spraying weeds in your dormant Bermuda lawn. Use a product containing glyphosate, found in Roundup and others. Use when the temperature is above 50 degrees and always read the label carefully before using.

•        Tomato seeds are best planted into indoor flats around Valentine's Day for mid-April garden transplants. Should you decide to grow your own tomato transplants from seeds, consult OSU fact sheet “Growing Tomatoes in the Home Garden,” which can be found on the Tulsa Master Gardener website. In that same section of the website, you will find additional fact sheets on growing conditions, pests and diseases, which are helpful.

Selecting and Growing Fruit Trees

Master Gardener: Fruit trees are bountiful in Oklahoma

Brian Jervis: Ask A Master Gardener

Saturday, January 21, 2017

Q: I would like to grow some fruit trees but not sure what would be the best type to for our area. Suggestions? L.M., Tulsa

A: There are many types of fruits that may be successfully grown in Oklahoma. These include the “pome” fruits (apples and pears), the “stone” fruits (peaches, nectarines, apricots, cherries and plums), as well as other fruits such as figs, persimmons and berries.

All these fruits vary in their ease of culture; some are relatively easy to grow and others need intensive management for good fruit production. Generally, apples and pears are the easiest of the tree fruit to manage, with peaches being the most difficult. Sweet cherries do not thrive in Oklahoma, but sour cherries do well. Most of the berries require much less management and can be grown more successfully than the larger fruit.

Additional considerations, when selecting fruit trees, are varieties best for our area, as well as the pollination needs of that particular tree. OSU has a number of fact sheets available online that detail this information.

Homeowners may find a dwarf tree may be the best fit for available space and ease of harvesting. These trees are common varieties of fruit trees, which are grafted onto a hardy dwarfing root stock. The fruit is the same from full-sized and dwarf trees.

Pollination requirements are most important. If ignored, you may end up with a healthy fruit tree with bountiful spring blossoms and no fruit. Some fruit trees are self-pollinating, but the majority need another variety of the same fruit type for successful production.

After deciding on the type of fruit to grow, the choice of a growing site is also important. Remember, the fruit tree will be with you (hopefully) for many years; plan with that fact in mind.

Most all fruits need full sun, up to 8 hours per day. They also need a soil with adequate drainage. They generally will not do well in high clay soils or in areas prone to flooding. One of the challenges of growing peaches, plums and apricots is the late spring frosts that kills maturing buds. To reduce the likelihood of this, consider planting trees on a north slope or the north side of a building. This will delay spring “bud-break” and reduce spring frost damage.

For fruit trees to be most productive, they should be sprayed for insects and disease. These sprays are generally needed just before spring growth and continued up to fruit harvest. Some of these schedules are complicated, and each recommended schedule is different from fruit to fruit. The OSU Tulsa Master Gardeners website, tulsamastergardeners.org, has a wealth of information about the management of all the fruits — when and what to spray with for each type of fruit.

Growing fruits can be rewarding as a hobby, especially for children. They can see “their tree”

Garden tips

Even though there may be adequate moisture in the ground, it is normal for evergreen broadleaved shrubs to appear “wilted” during extreme cold. This is rapidly reversible after the temperatures warm. This is a way some plants deal with the cold.

Try to keep fallen leaves off newly seeded fescue. Fescue is capable of growing roots in winter unless the ground gets extremely cold. A good root system will help fescue to better tolerate the heat next summer. To grow roots, the grass needs sunlight.

Growing Blackberries

Growing raspberries and blackberries takes planning

Bill Sevier Ask a Master Gardener

Saturday, January 14, 2017

Q: Do blackberries and raspberries grow well in Oklahoma? How does one get started? M.E., Tulsa.

A: Blackberries are the easiest of all fruits to grow in Oklahoma. Raspberries are similar; the plants grow well, but the weather — spring freezes and high heat in summer — limits berry production. As a group they are called “brambles,” and the discussion below applies to both. There are hybrids between these two such as boysenberries, dewberries and others.

Although easy to do, establishing a berry patch includes more than planting a few transplants in an existing garden bed in your backyard. A good place to start planning is with OSU fact sheet HLA-6215, “Blackberry and Raspberry Culture for the Home Garden.” This document discusses the essentials, which are site selection and preparation, variety choice, propagation and planting, and general care — mulching, fertilizing, irrigation, training and pest control. The techniques of harvesting are also discussed.

The berries need at least six to eight hours of sun. They tolerate a wide range of soils if well-drained. For wet areas or heavy clay soil, use raised beds. You should perform a soil test to get an idea of what amendments are needed. Blackberries prefer a pH of 5.5 to 6.5 (slightly acidic), and all beds will benefit from composted organic material tilled into the soil.

The University of Arkansas developed most of the new productive cultivars and most are well-suited to our area. They all are named after Native American tribes and are either thorned or thornless, and they grow upright. There are other varieties of blackberries with trailing habits, which means they need trellises for support.

Blackberries usually have two types of canes. The ones produced the first year are called primocanes. Two-year canes are called floricanes.

Primocanes rise from roots and grow to full height the first year. They do not blossom or have fruit. Primocanes turn into floricanes the following year. These canes bear fruit and die. This means that normally, you must grow blackberries for two years before getting any fruit, although there are a few new varieties that produce fruit on the primocanes in the first year. This also means that the floricanes need to be pruned out at the end of the fruiting season.

Blackberries are planted as either root cuttings or plants. They may be planted anytime during the dormant season but do best if planted in February and into March. No trellis or support is needed for the erect berry plants, but all will need a thick layer of loose mulch. They all will need fertilizer, usually twice a growing season. There is some additional tip pruning needed for best production, all discussed in the above referenced fact sheet.

After planting, the blackberries will need 1 to 2 inches of water per week by irrigation or rainfall. A drip irrigation is ideal for these plants. There also are some recommended disease and insect sprays recommended for the plants.

Garden tips

·       Several early season vegetables are grown from seeds and planted as sprouts or transplants. Some examples are cabbage, cauliflower, broccoli, head lettuce, onions, tomatoes, peppers and eggplant. Most of these take 5-7 weeks from planting indoors until ready for transplanting into the garden. Onions take a little longer to grow.

·       Of these, cabbage, cauliflower, lettuce and onions sprouts should be set out from mid-February to mid-March. Plant broccoli sprouts in March. Tomatoes, peppers and eggplants need warmth and suggested planting time is mid-April, although many people take a gamble and plant earlier, depending on the weather. Look for seeds at local gardening centers or online now if you plan on growing your own transplants.