It is so hot, I don’t even want to be outside for 5 minutes. I’ve let everything go in my lawn and

garden, to try and conserve as much well water as possible. I am trying to eek my tomatoes

and landscape plants through with occasional watering, even though I’m drenched with sweat by

the time I finish. I’ve noticed certain plants are weathering the drought better than others.

Slender Mountain mint, rosemary, Arkansas Bluestar, ‘Fireworks’ Gomphrena, lantana, Sedum,

Euphorbia, and Chaste tree are all fairing pretty well, considering the brutal conditions outside.

With the gripes about the heat and drought, I did freeze about 6 quarts of tomatoes. So I can’t

complain too much. For now, I’m going to enjoy the air conditioning, hope for rain and an un-

seasonably long autumn. Stay cool out there, and drink plenty of water! If you would like to be

added to the newsletter list, email me at tracey.payton@okstate.edu —Tracey

In Oklahoma we are a little behind in the areas of adopting green infrastructure and practices com-

pared to other states. However, some of this is out of our control. Hail can limit the use of traditional solar

panels, wind power may be a better option west of I-35, and you need rain to collect rainwater sufficiently.

Last week I attended an interesting symposium on green roofs sponsored by Oklahoma City. At first this

topic was a little intimidating, but once I learned a little about the practice it became intriguing. Green roofs

are defined as: built surfaces containing a substantial portion that sustains a permanent vegetative layer.

These living roofs have numerous environmental benefits to the homeowner and the community.

First, green roofs dissipate heat and reduce energy consumption. This can be a huge factor in ur-

ban areas and concrete jungles. In addition, green spaces are relaxing, fun to visit, and visually pleasing.

Furthermore, green roofs can lower the internal temperature of structures by as much as 10 degrees Fahren-

heit. This can save you money on heating and cooling costs.

Green roofs also have a positive return for businesses and employees. On average, there are fewer

occurrences of sickness and sick leave by employees with access to or a view of green roofs and spaces.

This can equal a more effective and efficient working environment.

Although initial installation costs per

square foot are higher, green roofs can last

longer than traditional roofs. Some experts

estimate a successful green roof lasting 2 to 3

times longer than shingled roofs. In addition

green roofing materials have lower mainte-

nance costs in the long run.

Additional benefits of green roofs

may include: increased building value, fire

prevention, noise blockage, catching storm

water runoff, improving air quality, and

providing wildlife habitat. There really are

too many benefits of green roofs that can be

listed or even measured. However, if you are

an employer, building a home, or looking to

update a structure to be greener, you may

think about installing a green roof.

Drought Continues Again This Summer I N S I D E T H I S

I S S U E :

What Not To

Do In a

Drought

2

Bug of the

Month

3

Landscape

Design Tip

3

Hot Plant

Pick

4 Green Roofs a Growing Option

C L E V E L A N D

C O U N T Y

E X T E N S I O N

H O R T I C U L T U R E

The Hort Nerd News A U G U S T 2 0 1 2

I N T H E K N O W

Master Gardener email questions:

ccmastergarden-er@yahoo.com

Access OSU Fact

Sheets online at:

osufacts.okstate.edu

For upcoming Cleve-

land County Horticul-

ture Events, see our

web page:

oces.okstate.edu/cleveland/

horticulture

Norman Farm Market

Every Wednesday and

Saturday, 8 am-12 pm.

Demonstration Gar-

den Tours, Saturday, 9

am-12 pm.

A view of the green roof on top of City Hall, Chicago.

http://land8.com/profiles/blogs/chicago-tops-north-america-for

P A G E 2

“Do not apply

fertilizer during

extreme heat and

drought.”

Drought Do’s and Don’ts Everyone is suffering in the lawn and garden department. Our trees and shrubs are scorching and dropping leaves. Your lawn is probably brown and brittle, unless you have a watering system. The Norman area is already experiencing severe drought con-ditions again this summer. Being a good steward and conserving water is always in style, but during drought conditions it can be especially important to conserve other resources. First, do not apply fertilizer during extreme heat and drought. Now is not the time to give your lawn, trees, or shrubs a boost. With our lack of soil moisture, fertiliza-tion will not be beneficial to those plants just trying to survive. In the lawn, I would suggest you do not fertilize until May 2013. Typically with warm season lawns, like Zoysia and Bermudagrass, your last month to fertilize is August. Unless we receive sig-nificant rain before August 31st, fertilization is not recommended. If you have allowed your lawn to go dormant, as recommended, you may resume watering 1 inch per week once temperatures cool off again.

Holding off on fertilizer goes for trees and shrubs, too. Summer 2011 was a bad year for plant health, and as a result most plants grew very little or went into an early dormant peri-od. Most fertilizer applied before or during last year’s drought may not have been utilized by the plants. In this case, you may still have excess fertilizer already present or the unused fertiliz-er may have ended up in storm water runoff. Dead and dormant plants use no nutrients. Wait to fertilize until condi-tions are ideal: when plants are healthy and actively growing. Second, the only way to know what is really going on in your soil is to perform a soil test. I’ve touched on this before, but Lake Thunderbird is on “life support” due to over applica-tion of nutrients. The future health of Lake Thunderbird de-pends on the consumer being smart about applying fertilizers. If you use organic fertilizers or compost, you are not exempt

from soil testing. It has never been more important to be conscious of how and when to fertilize. Only fertilize based on soil test recommendations. Lastly, do not apply any herbicides during hot, dry conditions. Most herbicide labels restrict applications during drought. Some chemicals can volatilize at high tem-peratures and drift can occur even at low wind speeds, causing irrevocable damage to desirable plants. Furthermore, herbicides may not be effective on drought affected, slow growing weeds. You may be wasting time, money, and sweat to treat weeds that won’t respond. In lawns es-pecially, herbicide sprays can damage dormant turf as well. Always read and com-ply with chemical labels, as ignoring the label is illegal and dangerous. Water restrictions and drought may become more common each summer. It is better to prepare now and know what to expect, than to be surprised by continuing summer warming trends.

T H E H O R T N E R D N E W S

Landscape Design Tip Corners in the landscape can be an eye sore and detract from the flow of

plant material. Soften a sharp corner by incorporating a small tree or shrub,

like a crape myrtle or chaste tree if the space gets full sun. Also use annuals,

perennials, or bulbs under or around the shrub to add interest. Keep scale of

homes, fences, or retaining walls in mind and know the mature height of

plants. Do not use grasses or needle leaved evergreens near the home, as

they can become a fire hazard.

P A G E 3 H N N A U G U S T 2 0 1 2

Large Wasps Creating a Buzz I came to work this morning and noticed a jelly jar on my desk that contained a large wasp. I wasn’t too sur-

prised; it’s not uncommon for my desk to have a plethora of jars and plastic bags on it. I glanced at the jar as I was go-

ing to get my coffee and knew it right away. It’s the time of year for cicada killer wasps to be out and active.

The adult wasp can be intimidating, as they can get as big as 1.5” with black and yellow stripes. The

female cicada killer wasps are capable of inflicting a painful sting, however they are hard to provoke and very docile

(unless they are fighting for their life inside a jelly jar). Mating males may be more aggressive, but are not equipped to

sting. All buzz and no bite. Cicada killers excavate a hole in the ground, so U-shaped mounds of dirt may be associated

with their burrows. These wasps are very common this time of year and may be more likely in areas where the soil is

bare, like between plants in flower beds and planters. They can also be found in the lawn, but are more uncommon in

healthy, thick turf. Cicada killers don’t feed on plants, the adults feed on nectar and the larvae feed on paralyzed cica-

das. Unlike some wasps and bees, these insects tend to be solitary and have a better attitude.

Cicada killer wasps overwinter in the soil and begin emerging as adults in June. For several weeks prior to cap-

turing cicadas, the adult female feeds on the nectar of nearby flowers, mates with a male, and digs burrows. These

ground nests tend to be vertical or somewhat angled, ½” wide and 6-10” deep. Perpendicular to the main tunnel, the

wasp will dig broad oval cells. Once the cells have been dug, the

search for prey begins.

The female adult cicada killer begins searching tree trunks

and lower limbs in search of noisy cicadas (some people incorrectly

call them locusts). Once the prey is found, the wasp stings the vic-

tim and turns it on its back, straddles it, and drags or glides with it

back to the burrow. Each cell contains at least one paralyzed cicada

where the wasp has laid an egg, and then the cell is sealed. When

the wasp egg hatches two to three days later, the legless larva will

feed on the insides of the cicada for 4-10 days, until only the shell is

left. In fall, the larva spins a silken cocoon to overwinter. Then the

cycle begins again. There is only one generation of the cicada killer

wasp per year.

If you have a very large population, say 10 or more in an

area with young children, treatment may be warranted. The best

means of control is a light dusting around the entry of the nest.

Products containing the active ingredient carbaryl, found in Sevin

Dust, are recommended. Be aware that this is a broad spectrum

insecticide and will kill most anything that comes into contact with

the dust. Wasp and hornet sprays may also work, but you have to

contact the insect with the spray, increasing the chances of aggra-

vating the wasp. I typically don’t recommend treating these insects

unless you absolutely have to. These wasps are considered benefi-

cial, and are also pollinators. Cicada killer wasps should be treated

with the same respect as bees, so consider using them as a teaching tool.

Photo courtesy of http://ccmgatx.org/design/hoadesignplans.asp

This plant makes me happy. Every

day when I pull into my driveway, I

see these happy little pink blooms

welcoming me home. The blooms

are still hanging on, despite the heat and wind.

They aren’t pristine, mind you, but to see the

splash of pink amid brown and scorched is a nice

sight. Gomphrena will get several feet high and

wide, so put it behind a shorter plant and give it

a little room to expand. (Mine is situated behind

a blue-green euphorbia border.) I typically don’t

believe in annuals, but this is one of only a hand-

ful that make my list. It’s tough, pretty, interest-

ing, and pink! What more could you want?

At the Cleveland County Fairgrounds

601 E Robinson

Norman, OK 73026

Phone: 405-321-4774

Fax: 405-360-0319

E-mail: tracey.payton@okstate.edu

The Oklahoma Cooperative Extension Service,

a division of Oklahoma State University, pro-

vides a link for the public to Oklahoma State

University research, tools, and practical infor-

mation. Through our 77 county based offices in

Oklahoma, we strive to provide a resource for

better growing, living, farming, communities,

health, and youth education programs.

The Oklahoma Cooperative Extension Service offers

its programs to all eligible persons regardless of

race, color, national origin, religion, sex, age,

disability, or status as a veteran, and is an equal

opportunity employer.

Cleveland County Cooperative

Extension Service

Hot Pick Plant

Bringing the University to You.

Fireworks Globe Amaranth

Gomphrena ‘Fireworks’

See our website: www.

oces.okstate.edu/cleveland/horticulture

Photos courtesy of greensparrowgardens.com and Bustani Plant Farm