How to Get Rid of Overwintering Pests (The Use of Dormant Oil and Horticulture Oil Sprays)

Posted on March 21, 2013 by Glenn

In a recent blog post, I talked about the fact winter’s colder temperatures, especially here in North Texas, do not necessarily kill all your lawn and garden pests – many live to fight another day. One way we battle these overwintering pests such as aphids, mites and scales before they become active in the spring is with dormant oil (sometimes called horticulture oil) sprays.

Dormant oils were originally developed to treat otherwise hard-to-control pest problems on fruit trees. These highly refined oils are sprayed on shrubs and the bark of trees during the winter months when plants are dormant (November through February). They kill difficult-to-eradicate microscopic pests
In a number of ways by either suffocating them or disrupting how they feed.

Dormant oils pose few risks to people and do not harm most beneficial insects. Toxicity is minimal, at least compared to alternative pesticides, and these oils quickly dissipate through evaporation, leaving little residue. Further, dormant oils also are easy to apply using proper spray equipment and can be mixed with many other pesticides to extend their performance.

That said, it is important to know what you’re doing when applying dormant oils, as improper application can lead to disastrous results. Dormant oils should never be applied to plants when there is a danger of freezing or when plants have emerged from dormancy. They should also not be applied to plants that are stressed out. In all of these instances, phytotoxicity can result (poisoning). Other plants such as pansies, bluebonnets and snapdragons growing under or near plants to be treated need to be completely covered and protected.

Recently, more refined oils have been developed that can be used for greater pest control during the growing season. Spider mites, whiteflies and young stages of scales are common pests that can be controlled by oils during the growing season.

Is a Cold Winter Good or Bad for Plants?

Posted on February 21, 2013 by Glenn

The short answer to this question is it depends on how cold, where you live and what types of plants you are trying to grow. In the Dallas area, our winters tend to be mild with cool temperatures interspersed with warm temperatures and a few freezes.

When is Cold Good?
Vernalization is a physiological process in some plants where the flowers or seeds must go through a prolonged period of cold in order to blossom or germinate in the spring. The amount of cold required by a plant is measured in “chill hours.” For many perennial plants, such as fruit trees, a period of cold is needed to break dormancy, prior to flowering. Peaches, for example, typically require 700 to 1,000 “chill hours” (below 45°F and above 32°F) before they break their rest period and begin growth. Nuts trees and berry bushes also have varying chilling requirements. That pretty much sums it up for cold = good.

When Cold Bad: Frosts and Freezes
To understand frost, you need to understand a little bit about dew point. Dew point is a water-to-air saturation temperature. When the temperature falls to the same temperature as the dew point, dew forms because that is temperature at which the air can no longer hold all its moisture. When the dew point is below freezing, frost forms instead of dew. Frost typically forms when the temperature drops to near or just below freezing and there is no wind. Frost can form when the temperature is above freezing, but frost is a sign that the plant tissues have dropped below freezing. When you see frost there has been a freeze at the point of the plant surface. The absolute low as well as the length of time frost conditions remain can affect how much damage is done to plants. Real damage occurs when the water in a plant’s cells freeze, damaging the cell wall.

When a plant is frost-damaged, growth can take on a translucent appearance or become limp, then turn black or brown and dry up. Frost problems can be worse where plants face the morning sun because they defrost more quickly, which ruptures their cell walls.

A freeze is a more extended period of below freezing temperatures and may or may not include wind. In the Dallas area, extended periods of freezing temperatures are rare. When they do occur, soil becomes frozen. Many people think that trees and shrubs “go dormant” in the winter. This is true, but the internal functions of plants do not stop, they just slow way down. As long as the soil is not frozen, trees, shrubs, and even some perennials will still be growing roots. When soil becomes frozen roots are unable to take up water and plants can die from lack of moisture.

Plants are most vulnerable to freezing temperatures in the spring when periods of warm weather increase and suddenly there are several nights with temperatures well below freezing. A hard freeze can damage fruit and buds. Buds may freeze and drop off or fully opened flowers can turn brown or fall to the ground.

Why Overseed Your Lawn

Posted on November 28, 2012 by Glenn

As the term suggests, overseeding is spreading grass seed over an existing lawn. There are basically two reasons for overseeding lawns. One is to maintain a healthy, thick lawn, which you do by keeping your grass young, and the other is to avoid an unappealing brown lawn during the winter. With these two different goals there are two slightly different approaches.

Overseeding Warm-Season Grasses with Cool-Season Grass
Because we are in Dallas, Texas our clients’ lawns have warm-season grasses, such as Bermuda grass, buffalo grass, St. Augustine grass or zoysia grass. In the winter when these grasses go dormant, they turn brown and unappealing. By overseeding a lawn with ryegrass, a cool-season annual grass, you can enjoy an attractive green lawn year-round. Another benefit of overseeding your lawn in fall is that it helps reduce weeds, crowding them out naturally, without resorting to chemical weed killers. Importantly, annual ryegrass will die back when the heat returns so that warm-season grasses can take center-stage again. It should be noted, however, that overseeding can also place stress on the primary lawn. In the spring when the warm-season turf is trying to come out of dormancy, the cool-season rye grass is still coming on strong, creating competition and slowing the primary grass growth. Especially in the shade, this can be detrimental for the warm season grass.

Overseeding Cool-Season Grasses with the Same Type of Grass
Not every cool-season grass benefits from overseeding. Grass types that spread by the production of “runners” are not typically overseeded unless the lawn is damaged or diseased. Cool-season bunch type grasses such as fescue grasses, ryegrasses and occasionally bluegrass benefit from overseeding.

The reason to overseed cool-season grasses is to keep your lawn looking thick and healthy. The easiest way to do this is by keeping your grass young. To understand this, it helps to understand a little about how bunch grasses grow. As the name suggests, bunch type grasses grow in a bunch. The grass crown, at the plant’s center, has roots and blades. Grass plants expand as new grass blades or “tillers” develop and grow next to the original crown. A blade of grass has a lifespan of about six weeks and must continually produce new tillers or the grass thins out. Hundreds of new tillers can develop, each having its own crown, roots and blades. After several years, mature plants begin to slow down their reproduction rate. Since new growth must outpace dying grass, it is important to keep young grass in the mix that will produce tillers faster than older grass.

When to Overseed Your Lawn
Whether it’s for warm-season or cool-season grasses, the time to overseed is fall when soil temperatures are still warm (necessary for seed germination), air temperatures are cooler (better for grass growth) and there is more rain. Additionally, cooler temperatures reduce insect infestation and disease.

Green Gardening Flea Control with Nematodes

Posted on June 11, 2012 by Glenn

In the never ending quest to live more organically and naturally, there’s a new way to give your pets a break during the hot Dallas summer months. Treating your garden with nematodes (a type of roundworm) will help flea-proof your pets and your home. Nematodes happily munch on grubs, Japanese beetles, fleas, fly larvae and more than two hundred other pests without disturbing your unique eco-system with chemicals or pesticides.

You can find nematodes at home improvement stores, garden shops, or order them online. If you order online, the nematode container will arrive wrapped in cold packs to keep these helpful creatures alive when you introduce them into your soil. The beneficial types of nematodes (non-parasitic) are toxic to pests but safe for plants, animals and humans. They already occur naturally in soil and once they have completed their dining excursion they die off and biodegrade.

Application is a breeze. Simply spray nematodes on wet soil with a garden hose twice a year, during spring and fall. The nematodes will burrow in the ground, rooting out your flea population and devouring it. Over time, you’ll find your flea population is significantly reduced at an economical price (under $20) and your pets are scratching significantly less.

Garden Up with Green Walls

Posted on April 6, 2012 by Glenn

contemporary residence with pool and vertical garden or green wall

Photo courtesy of greenovergrey.com

Green walls, vertical gardens or living walls are gaining popularity both inside and out and I love the idea. Like most ideas, it isn’t exactly a new one. The practice of planting ivy to climb up the walls of buildings has existed for centuries. The new vertical gardens are simply a natural extension of this concept. So far, they seem to be predominantly cropping up in city environments, but we predict you’ll see more and more of this trend spreading to the ‘burbs.

Vertical gardens offer a number of benefits. The most obvious is esthetics; they can make structures more attractive and add fragrance. They can create an inviting habitat for urban wildlife. They also help absorb sound and improve air quality indoors and out. Green walls decrease CO2 and increase humidity. (Although how much they improve air quality is a pretty hotly debated topic – as are some of the other pros versus cons of green walls.)

Green wall or vertical garden on a residential rooftop patio.

Photo courtesy of agreenroof.com

Other positive claims: exterior green walls reduce solar gain (the increase in temperature in a structure that results from solar radiation) thus lowering energy costs, they provide protection from the effects of UV radiation and acid rain, and help lessen the building’s contribution to the heat island effect (when natural areas are replaced with concrete and asphalt, they become warmer).

So what are the potential negatives to green walls? The biggest concerns fall into three general categories: 1) over-inflated claims regarding the benefits (don’t expect to save 20% on your energy bills!), 2) the debatable trade-offs that relate to sustainability – for example, a number of the grid planter systems on the market are made of plastic, and 3) the long-term sustainability of the walls.

Side-by-side photos of green wall on PNC Bank

PNC Bank in Pittsburgh Sept. 2010 and Feb. 2011

Of these, the third is not something you read or hear a lot about, but it is perhaps the most important. While properly constructing and installing a green wall or green panel (after all, green walls don’t need to be an entire wall) isn’t exactly a cakewalk, maintaining a green wall is the bigger challenge. If many or all of the plants need to be replaced frequently one has to question the sustainability.

The reality is, to successfully maintain a green wall on anything but the smallest of scales is best left to experts. It requires an in-depth knowledge of design, irrigation, plants, growth media, pest and disease management and fertilizers. Choosing the right system, the correct plants for the setting and understanding the science behind the technology are all keys to green wall’s longevity.

As I said at the beginning of this post, I love the idea of green walls and vertical gardens. I’ve seen lots of striking examples, the most dramatic being some of the commercial applications. (Although personally I also love the small, less ambitious and more maintainable residential efforts.) The key, as with any landscaping effort, is in getting all the variables right for sustainability.

The Glamour of Gravel

Posted on March 12, 2012 by Glenn

Black Basalt

Gravel may not seem like the most glamorous of subjects, but you know the old saying, “beauty is in the eye of the beholder” and like most of the landscaping materials I work with, I love and appreciate gravel as a diverse landscaping solution with its own unique features and benefits. There is a lot more to gravel than the drab grey stuff that probably popped immediately into your head at the mention of the word. Many types of rocks are crushed and used for gravel and like flagstone, come in an array of colors from Black Basalt to Pennsylvania Bluestone.

Colorado River Rock

Benefits and Uses of Gravel
Gravel telegraphs a more organic feeling and softer mood than most other kinds of paving. It can be casual or formal, traditional or modern, depending on the type chosen and how it is used. Gravel will last a lifetime and provides excellent drainage, allowing water to readily flow through to the dirt underneath.

Here in the Dallas area, a number of communities have ordinances that limit the amount of impermeable surface allowed on a property. So, for example, if you have a large house with a pool and concrete decking on a small urban lot, a gravel driveway and footpaths may be more than just an esthetic choice. Ordinances aside, in a draught-prone climate such as ours, gravel, because it is permeable, can certainly be considered a more practical and environmentally friendly choice than concrete.

Decomposed Granite

Gravel can be used for driveways, walkways, patios, play areas, for “petscaping” and is a great choice for mulch. It is low-maintenance, relatively inexpensive and attractive. Gravel has long been used in some of the more arid climates of the Southwest in sparsely planted dessert gardens and even as a green, sustainable alternative to lawn. (Since landscaping typically accounts for 20-50% of all residential water use, the savings can be significant.)

A gravel surface will last indefinitely, but it does require some minimal upkeep that includes occasional weeding and every few years, top-dressing of some new gravel.

Decomposed Granite

Types of Gravel
Gravel comes in a variety of colors, shapes, sizes and materials. What you choose will depend on how you are going to use it along with personal preference. Gravel can be rocks that are mined or tumbled with rounded edges (commonly referred to as river rock), or mechanically crushed to make sharp angular edges (crushed rock). Rounded edges are softer underfoot but are more likely to shift because they are smooth. Crushed rock locks together for a more stable surface, which makes it a better choice for driveways and other high traffic areas. (Other types of gravel, such as pea gravel can be used for driveways and function and look beautiful, however, they are created using a mix that includes crushed granite or concrete to make the surface more stable.)

Mexican Beach Pebble

Today there is a huge range of color options in gravel (although you may have to invest some time and energy to discover all your options if you aren’t relying on a professional landscaper since the selection at the mega hardware chains isn’t that great). Mixed gravels contain many shades of color and mixtures with agate and feldspar can almost seem jewel-like. (These are a good choice for smaller projects that will be seen close up.) Some common types of gravel include:

Black Basalt Gravel

• Crushed Gravel – What you typically think of when you think of gravel. It’s gray and is made up of sharp and irregularly shaped rock fragments, which makes it easy for the rocks to interlock and compact.
• River Rock – Smooth stones that are softer underfoot, provide good drainage and come in a variety of colors, typically grays and browns and typically range in size from 3/8 inch to 6” inches. River rock is often used in flower and garden beds and on walkways for erosion control. (We used river rock in for the fountain beds in two photos featured in this post.)

New Mexican River Rock

• Pea Gravel – Pea gravel is simply smaller sized river rocks and are sandy in color. (We used a pea gravel mixture for the circular driveway featured in this post.)
• Lava Rock – Lava rock is lightweight and porous with angular edges, offering good drainage and usually ranging in size from ¾ inch to 1-1/4 inches. It comes in red or black hues. (We use lava rock a lot for fire pits, however, the black is increasingly hard to find.)
• Quartzite – Quartzite is small, like pea gravel, but a brighter, white color.
• Brick Chips – These are crushed, angular fragments of terra cotta brick ranging from ¾ inch to 1-1/4 inches and are typically used for driveways or as mulch.

Crushed Granite

• Crushed Marble or Granite – Among our favorite materials for walks, patios and drives. Crushed marble comes in varying sizes and a wide array of colors – reds, greens, golds, yellows, blacks – making it highly versatile. It always looks great and works in many different types of settings.
• Decomposed Granite – DG is readily available gravel that comes in ½ inch to fine powder. This is one of the best materials for drives and walks. It is an orange/brown color.
• Limestone – A great material that is also readily available. It comes in a variety of different sizes from, 3/8 inch – fine powder or dust for walks, drive and patios and up to 3-6 inches for use as small rip rap.

Hopefully, as you’ve been reading this post you have also been enjoying the photos that show some examples of how we use gravel to create beautiful and practical outdoor landscape environments. And maybe, just maybe, you’ll agree with me that gravel can be glamorous.

March Landscaping in Dallas: Cutbacks, Pruning and Planting

Posted on March 2, 2012 by Glenn

Is it just me, or did winter pass us by this year in Dallas? As I write this I see the forecast for today is 80 degrees (!) and the extended forecast is upper 60s and low 70s. It appears spring is, well, springing. Here at Bonick Landscaping, we are busy doing cutbacks or pruning. While not the most glamorous of landscaping activities, it’s an important one for plant and landscape health.

Proper Pruning
Properly cutting back or pruning of trees, shrubs, grasses, roses and perennials enhances the beauty of your landscape, but like any other skill, it does require knowledge of what you are doing to achieve success. In most cases, it’s better not to prune than to do it incorrectly as improper pruning can weaken, deform and even kill plants. Believe it or not, more trees are killed each year from improper pruning than by pests. Often DIY pruners don’t have a good fundamental understanding of plants – that the leaf surface reflects the root system, for example, and if you take out too much leaf system, the roots die back – add drought conditions to this equation and all of a sudden you are looking at a once healthy tree that is struggling to survive.

Reasons for Pruning
Reasons for pruning are to maintain plant health, improve the quality of flowers, fruit, foliage and stems and in some instances to restrict growth or “train” a plant. Pruning should always follow a plan that begins with understanding the reason for pruning before you begin. The most obvious reason to prune is to remove dead, broken, pest-infested or diseased limbs by cutting them at the point of origin or back to a strong lateral branch or shoot. Pruning beyond this basic level gets a bit trickier, and again, should only be approached when you are confident that you know what you are doing.

Don’t forget to cutback groundcover and grasses, too, to allow for new growth. It should go without saying, but at this point, wait to trim spring-flowing shrubs and vines until after flowing.

Other March Landscaping Activities
Remember, now is also a good time in the Dallas area to plant trees, shrubs, roses, perennials, herbs and annuals such as begonias, petunias, geraniums, alyssum and snapdragons. Did I mention roses? Some people don’t realize that there are many drought tolerant roses that grow well here in the Dallas area. If you are a DIY gardener, your local nursery can steer you in the right direction. In fact, our friends at North Haven Gardens will be hosting their Spring Rose Festival this weekend, March 3 and 4 and have several educational sessions about roses scheduled throughout the weekend.

These next few months in Dallas are truly some of the most pleasant times to be outside and gardening so enjoy!

Reflections on the Joys of Gardening

Posted on February 16, 2012 by Glenn

A while back I read a great opinion piece, “The Joy of Quiet” that talked about how “the average American spends at least eight and a half hours a day in front of a screen…in part because the number of hours American adults spent online doubled between 2005 and 2009 (and the number of hours spent in front of a TV screen, often simultaneously, is also steadily increasing).” It went on to site research findings that indicate “that after spending time in quiet rural settings, subjects “exhibit greater attentiveness, stronger memory and generally improved cognition. Their brains become both calmer and sharper.” More than that, empathy, as well as deep thought, depends (as neuroscientists like Antonio Damasio have found) on neural processes that are “inherently slow.”

I am fortunate to work in an industry where I get to spend at least some time contemplating nature, although admittedly, usually from my office window. Today’s post is simply a random collection of quotes I have collected that I hope serve as a gentle reminder of how rejuvenating the act of gardening is and how important it is to stay in touch with nature.

• The best place to find God is in a garden. You can dig for him there. – George Bernard Shaw

• I think this is what hooks one to gardening: it is the closest one can come to being present at creation. – Phyllis Theroux

• When heaven falls to earth it becomes a garden. – Stoufer

• Everything that slows us down and forces patience, everything that sets us back into the slow circles of nature, is a help. Gardening is an instrument of grace. – May Sarton

• A man has made at least a start on discovering the meaning of human life when he plants shade trees under which he knows full well he will never sit. – D. Elton Trueblood

• I do some of my best thinking while pulling weeds. – Martha Smith

• Garden as though you will live forever. – William Kent

• I grow plants for many reasons: to please my eye or to please my soul, to challenge the elements or to challenge my patience, for novelty or for nostalgia, but mostly for the joy in seeing them grow. – David Hobson

• Autumn is a second spring when every leaf is a flower. – Albert Camus

• Grow what you love. The love will keep it growing. – Emilie Barnes

• Don’t judge each day by the harvest you reap but by the seeds that you plant. – Robert Louis Stevenson

• Working in the garden gives me something beyond the enjoyment of the senses. It gives me a profound feeling of inner peace. – Ruth Stout

• No two gardens are the same. No two days are the same in one garden. - Hugh Johnson

• Someone’s sitting in the shade today because someone planted a tree a long time ago. – Les Brown

• He who plants a tree, plants a hope. – Lucy Larcom

• Gardening is the art that uses flowers and plants as paint, and the soil and sky as canvas. – Elizabeth Murray

A Warm Winter and Growing Bulbs in Dallas

Posted on February 1, 2012 by Glenn

photo courtesty of Doug Green's Garden

We are having an unseasonably warm winter, even for Dallas, and one of the results has been gardeners have already begun to see some spring bulbs sprouting and have been asking me about it. Some gardeners worry that their plants may die if a sudden cold spell hits (remember the snow we had last February?) The good news is your plants are hardier than you think.

Right now, most of what you are seeing is foliage (rather than buds and blooms) which can withstand cold temperatures. However, if the flowers actually bloom, then there is reason to be concerned if a cold snap is in the forecast. If you are concerned about your bulbs experiencing shock due to frost, you can cover them with a frost blanket. Your other option, of course, is to cut a bouquet and enjoy the blooms in the house. Realistically, the latter may be your best option with daffodils as they can be most affected by a late cold snap. (It’s also a good reason to consider planting early, mid-season and late-blooming daffodils.)

If your plants do develop flower buds and are damaged by the frost, it is normal for emerging buds that have been affected by frost to turn yellow or brown and drop off. This is an indication that the plant is returning to dormancy and may bloom again once the warmer weather returns. If your bulbs have flowered, they could be damaged for the rest of the year but should continue to grow in later years.

Landscaping Under the New Water Restrictions

Posted on January 23, 2012 by Glenn

Dallas is experiencing its fourth drought since 2000. We went into Stage 1 water restrictions on December 12, 2011 and meteorologists are currently predicting that the drought will continue at least through the summer. Nearby areas such as Frisco and Plano are in Stage 3 water restrictions, that mandate watering no more than one time a week.

It seems to me that “the writing is on the wall” in that smart Dallasites will move toward landscaping designs that involve more draught-tolerant plants. Stage 1 water restrictions mandate that watering can be done twice a week but if draught conditions continue, restrictions could become more severe. Either way, many of the lawns and landscapes I see around Dallas simply aren’t “simpatico” with the concept of water conservation.

As a professional landscape designer, I understand the challenges this presents. The palette of draught-tolerant plants simply isn’t as broad, but there is still plenty to choose from. It is important to remember that just because a plant is native to Texas, doesn’t necessarily mean it is draught-tolerant and that the Southwest, Mexico, Australia, New Zealand, South Africa, Chili and the Mediterranean all are sources for beautiful plants that come from climates that are similar to ours. Among my personal favorites are native grasses, they are great for adding drama and focus to an environment. Other plants I love that are draught tolerant include rosemary, yuccas, agave and roses.

What can you do in the meantime to optimize the appearance of your landscape while moving toward a more draught-tolerant landscape? Here are some general tips:

Water restrictions mandate that all watering take place between midnight and 10 a.m. and 6 p.m. and midnight. Because it stays hot into the evening in Dallas, it is better to water lawns during the early morning hours when temperatures and wind speed are at their lowest. This reduces evaporation and waste.
Cycle soak. This allows the soil to absorb all that is applied, avoiding runoff. The length of the cycle will vary based on the conditions of the landscape, but you want to schedule several short cycles about an hour apart in order to allow the water to absorb to a depth of about 6-8 inches. This is the most important thing that we can all do to save water and improve the health of the plants. We have successfully kept many landscapes alive in Frisco when we were only allowed to water once a week in 100+ degree weather by cycling the water 3-5 times to get a deep soak without runoff. This also helps to promote deep foot growth where the soil stays much cooler.
Raise the lawn mower blade to at least three inches, or to its highest level. A higher cut encourages grass roots to grow deeper, shades the root system and holds soil moisture.
Avoid over fertilizing your lawn. Applying fertilizer increases the need for water. Apply fertilizers which contain slow release, water-insoluble forms of nitrogen.
Install irrigation devices that are water efficient. Micro and drip irrigation and soaker hoses are examples. The most important thing is to make sure that your irrigation system is well-designed and operating properly.

The reality is that the current water restrictions are simply forcing us all to do something we should be doing anyway and that’s reducing the amount of water used in our landscapes though good water management practices. Maintenance becomes even easier when these best practices are combined with draught-tolerant plant choices. Do you have a favorite draught-tolerant plant? How well did your landscape survive last summer’s heat wave and our current draught? We’d love to hear from you.