Hydrangeas are failing to bloom

QUESTION: “I have two hydrangea plants that grow every year in a sunny location, with large bright green leaves. The plants never make flowers, however, even though the woman who gave them to me years ago took the small plants from her garden where she had many flowering specimens.

“At the end of the summer, I have those long spikes which I carefully protect through the frosty winter, but by spring they are dried up and appear dead. As the new leaves start to grow, I lose hope and cut the pale spikes down. Most of the time, the deer eat the tops anyway. Any hope? Should I transplant them?” – Faith Gitlow

ANSWER: Hydrangeas can be tricky. According to the experts at www.hydrangeashydrangeas.com (my favorite hydrangea care site) there are three main reasons why hydrangeas fail to bloom:

1. A late spring freeze arrives and ruins the developing bloom buds.
   
2. Improper pruning.
   
3. Planted in wrong zone. If you have had the bad luck to plant a hydrangea that has not bloomed after the first year you planted it, you may finally have to concede that this particular variety is not cold hardy in your area.
   

If you go to their Web site you can find more information about all kinds of hydrangea problems.

QUESTION: “I have a problem with my blossoming Kwanzan cherry tree. The leaves are turning brown and falling off. Is it dying? I live in the California sierra foothills (elev. 1500ft.). It can get very hot during the summer months. The tree is planted in the middle of my lawn on an island of top soil with 2" of wood mulch on top. The island is about a foot and a half high and less as it spreads out.

“I water about every other day for 20 minutes at 4am. There are plants and flowers around it but not any closer than 2 ft. It also has new growth coming in. I just don't get it! Do you have any ideas?” – Dan Buchholz

ANSWER: Over the past four years or so, flowering cherry (and other varieties including birches) trees have been going dormant earlier and earlier each year where we live here in Tennessee which is zone 7. For the most part, it is attributed to the lack of rainfall (actual drought some of the years).

Around early to mid August, they begin to lose their leaves. Their coloring doesn’t fade to a lovely fall color, just brown. As long as there are no other issues with the tree, I would say it is the same problem. Cheryl and I have been receiving many emails this summer concerning trees doing this.

QUESTION: “For the past three seasons my pin oak trees have lost their leaves in August. The leaves turn translucent first before falling from the tree. I have used an insect treatment that you add to water and pour at the base of the tree for the past three years and it doesn’t seem to help. In the spring and during the summer the trees are full of leaves but in August they turn white and fall off the tree. The trees are 30 to 40 feet tall (I have two of them on the west side of my home).” – Susie Brown

ANSWER: Here is a link to the University of California at Davis Extension site with an article on diagnosing oak tree diseases.
http://ceventura.ucdavis.edu/newsletterfiles/Landscape_Notes11016.pdf
This article will give you a detailed listing to work with, but the most common reasons for early leaf loss with oaks is lack of water or cool wet spring/summer weather which typically causes fungus.

If you can’t figure it out with the article, contact your local agricultural extension agent for their opinion and how to proceed. To find the Extension Service nearest to you, visit this Web site: http://www.csrees.usda.gov/Extension/ or go to my Web site www.landsteward.org find this column and click on a direct link. Good luck!

The Plant Man is here to help. Send your questions about trees, shrubs and landscaping to steve@landsteward.org and for resources and additional information, including archived columns, visit www.landsteward.org

Deer-resistant plants mean less landscape damage

I think we’d all agree that deer are hungry critters. However much you enjoy wildlife, you can be disheartened, or even outraged, to find your prized shrubs chewed down to the stumps with tell-tale hoof prints in the surrounding soil.

In the previous Plant Man column, I described ways to determine if deer are the real culprits, and I took a look at some deer repellent products, both commercial and home-made. If you missed that column, you can find it at my Web site www.landsteward.org

Today, we’ll take a look at some deer resistant plants. As far as I know, there are no “deer-repellent” plants; the kind that would send deer scurrying away in panic. No such luck. So your best bet, if deer are a potential problem, is to select plants that hold the least possible attraction to deer. Unfortunately, in times of scarcity, deer will eat almost anything green, but you can put the odds in your favor so they will ignore your landscape in search of greener – and tastier – pastures.

Do a little homework and you’ll quickly discover which plants attract deer and which plants they find less desirable. A good place to start is http://njaes.rutgers.edu/deerresistence/ a Web site hosted by Rutgers University.

That Web site consists of a long chart of alphabetically-listed plant names, color-coded to indicate which are rarely damaged, seldom severely damaged, occasionally severely damaged or frequently severely damaged.

Using the Rutgers chart, you can determine if a plant on your wish list might be better replaced with a less deer-yummy one. Although it’s a long list, I can think of other plants that you could select when deer are a potential problem. Here are some to consider:

Boxwood Wintergreen (Buxus microphylla)
I’ve found that deer don’t particularly care for the taste or aroma of boxwoods under normal circumstances. This popular low growing evergreen shrub is commonly seen as a low hedge or border defining the edges of formal and informal gardens. The Wintergreen Boxwood offers dark green lustrous leaves and creates a striking hedge with year round color, holding its green color all winter long. Suitable for USDA zones 5 – 9.

Black Eyed Susan (Rudbeckia Goldsturm)
Black Eyed Susans are true perennials, returning larger each year. They are great for mass plantings and provide wonderful contrasting colors when paired with ornamental grasses, Shasta daisies, Russian sage or dianthus. Black Eyed Susan should be deadheaded regularly for continued blooms. They are a native North American wildflower as well as being deer and rabbit resistant yet attracting butterflies. Zones 4 – 9.

Barberry Rose Glow (Berberis thunbergii)
This is an eye catching form of Japanese Barberry, emerging with early foliage that is a rosy glowing pink color that turns a crimson burgundy as it matures. Full sun produces the best foliage, looking good as foundation, border or mass planting. Barberry Rose Glow needs a well drained area and can tolerate some drought in zones 4 through 7.

American Holly (Ilex opaca)
You probably wouldn’t relish eating holly and, as a rule, neither do deer. Left untrimmed, American Holly can reach a height of 30 feet or more with a spread of 18 to 30 feet. Bear in mind you will need at least one of each sex to produce berries that will attract birds and butterflies but not deer. Hardy in zones 5 to 9.

Bamboo Sunset Glow (Fargesia rufa)
A favorite of the Giant Panda but not that attractive to deer. This is a clumping (non-running) variety. Growing to 8 feet in height, the orange-red sheaths and deep green leaves will provide a nice hedge or screen at maturity when planted in groups. USDA zones 6 – 9.

Sage, Thyme and Chives
Deer don’t particularly care for these herbs but humans do, so they’re not a bad choice as attractive groundcover and as a great, fresh addition to many home-cooked dishes.

Again, no plant is 100% deer-resistant. But when you select plants that are less attractive to deer and employ some of the deterrents we discussed in the previous column, you should find that deer will generally look elsewhere for their salad buffet.

The Plant Man is here to help. Send your questions about trees, shrubs and landscaping to steve@landsteward.org and for resources and additional information, including archived columns, visit www.landsteward.org