Month: July 2022

If you listen closely you can hear the beasties in your garden just a-singin’ that tune. And who can blame them? Warm temperatures and lush green gardens? They enjoy them as much as we do. But sometimes they can be enjoying our landscape a little too much. So now what do you do?
Visit the garden chemicals section at your local big box store?
Reach for your favorite “natural” or DIY concoction?
Ask your neighbor?

What is the best way to deal with the problem?
Three letters answer that question.
IPM.

What is IPM? Integrated Pest Management (IPM) is the management approach you should use to solve pest problems. It can manage all sorts of pests with minimal risks to people, pets, and the environment. IPM’s emphasis is on the management of problems rather than eradication. It focuses on long-term prevention of pests or their damage by managing the ecosystem.
IPM is a five step process: 1) correct pest ID, 2) monitoring and assessing pest numbers and damage, 3) pest ID guidelines for when management action is needed, 4) preventing pest problems, and 5) determining correct control measures. Let’s take a look at each one.

#1. Pest ID

Correct ID of the problem-causing critter is the most important aspect of IPM. If you don’t know what you’re dealing with, how can you devise an effective control strategy, if indeed one is needed?
So what is a pest? Pests are organisms which damage or interfere with desirable plants or damage structures. Pests also include organisms that can impact human or animal health. Pests may transmit disease or may be just a nuisance. A pest can be a plant (weed), vertebrate (bird, rodent, or other mammal), invertebrate (insect, tick, mite, or snail), nematode, or a pathogen (bacteria, virus, or fungus).
A correct ID of the pest must be made before deciding if control is needed. If you aren’t sure you’ve ID’ed it correctly or want a second opinion, take a sample to your local Cooperative Extension Service Office.
Note: Be careful about asking for pest ID at a garden center. Employees may not be knowledgable, or your request might be seen as a sales opportunity. And think twice before taking the advice of someone who might try to sell you something.

#2. Monitoring and Assessing Pest Numbers and Damage.

You’ve probably heard the saying, “The best fertilizer is the gardener’s shadow.” I’ll make the claim that “The best pest control method is the gardener’s shadow”.
For effective monitoring, you need to be out in your garden on a regular basis. Looking, listening, even handling plants, checking under leaves, etc., so you come to know it as well as you know the layout of your living room. You should have a good knowledge of your landscape’s microclimates, soil conditions, the path of sunlight through the year, how seasonal changes affect your garden and a general grasp of the climate. Once you know what’s “normal” for your landscape it’ll be easier to spot any abnormalities.

For example:
Your favorite rose always has a few aphids but the population seems to have exploded in the last few days. And why do some of them have wings?
Is that slug damage on that hosta?
You don’t recall seeing those rusty patches on that hollyhock before.
What are the odd black spots on this pomegranate?
Hmm….
Always ask yourself how extensive the damage is. Does it threaten the health or life of the plant, or is it largely cosmetic? Do you need more expert advice?
Continual monitoring and assessing of what’s going on in your landscape can help you decide if the damage is important or extensive enough to require pest management.

#3. Pest ID Guidelines to Determine if Management Action is Needed

Using the biological information of the correctly ID’ed pest will help you decide if you need to deal with the situation. Here are some things to consider when deciding if management is needed.
Is the pest short-lived and is only in the garden for a few weeks or even days?
Does it only make a seasonal appearance?
Is the damage of long duration/the entire growing season, only for a short time and the plant recovers, or is the damage mostly cosmetic?
Is it a pathogen?
Does it carry a pathogen?
Can it cause irreparable harm?
Is it an invasive species that can or should be controlled?
Does it threaten a needed food garden?
Is the damage really that bad?

Knowing the life cycle and feeding habits of your ID’ed pest will help you determine if control is necessary. Use their biology against them. Do your homework.

So you have a plant issue and you’ve correctly ID’ed the pest and the problem. It needs to be dealt with.
What’s your next step?

#4. Preventing Pest Problems

“An ounce of prevention is worth a pound of cure.” applies to landscapes as well our personal health.
Ask yourself if the garden problems you’re facing, most of which will be cultural, can be handled with preventative measures.
Are you over or under watering? This stresses plants which can attract pests.
Is the plant that is under attack in a less than optimal location? Can you move it or change its environment to help it become healthier? Or should you just remove it and let the Japanese beetles eat somewhere else?
Are you practicing good garden sanitation, are you cleaning up those camellia leaves and blossoms after they fall, are you turning that compost pile and ensuring it heats properly in order to kill pathogens or pests?
If your growing zone allows it, perhaps you could plant your summer squash or tomatoes later and avoid that first rush of squash bugs or hornworms? (Keep in mind that hornworms are larval sphinx moths which are an important bat food source.)
Have you tried using row cover to exclude problem insects or other pests?
Be sure you’re not causing the problem. A little garden evaluation can do a world of good.
The decision you make here will determine the road you take in dealing with your pest issue. You’ve identified the pest, done some sleuthing and have an idea of the scope of the problem in your landscape. Now you have to decide what is the acceptable level of this pest to have in your yard.
And as always, “Right Plant, Right Place”.

#5 Determining Correct Control Measures

After analyzing the situation you’ve determined you need to engage in some form of pest control. But what should you use? Always strive to use the most benign yet specific form of control you can. Use the method which best targets the problem.
A combination of control methods usually give the best results. These include biological, cultural, mechanical/physical, and chemical/bio-rational measures. Start at the base of the pyramid (see above image) and work your way upward. Always allow sufficient time for methods to yield results. Pest problems rarely happen overnight. Early intervention is the key to control. See #2 above.

If you are forced to use pesticides always use them as a last resort, not as a first option.
Avoid using systemics on plants which are used by pollinators or other beneficial insects.
Avoid using broad spectrum pesticides and keep in mind that many pesticides which are approved for “organic” use are more toxic and less selective than “synthetics”.
An exception to the “avoid broad spectrum pesticides”: there can be times when a broad spectrum herbicide, such as glyphosate, is needed to kill both monocots and dicots. Use with care and follow label directions.

To review:
Please follow the IPM Five Step Process:
1. Always ID the pest correctly.
2. Get to know your own landscape. Monitor and assess pest numbers and damage to determine if intervention is truly needed. It often isn’t.
3. Use the pest’s life cycle and feeding habits to decide if or when management action is needed. Use their biology against them.
4. Prevent pest problems in the first place. Be sure you’re not part of the issue. “Right Plant, Right Place.”
5. If necessary, determine the correct control measures and always choose the most benign method which will do the job. Keep in mind products labeled “natural” may not be the best or safest option. Avoid DIY concoctions. They’re usually ineffective, harmful and an illegal use of ingredients.

Want to learn more about IPM?
http://www.npic.orst.edu/pest/ipm.html
https://ipminstitute.org/what-is-integrated-pest-management/
https://www.usda.gov/oce/pest/integrated-pest-management
https://www.epa.gov/safepestcontrol/integrated-pest-management-ipm-principles
Regional IPM centers

And last but not least:
* Link to my favorite cover of this great George Gershwin tune

If you live in a place where water falls from the sky during summer this blog is perhaps not so helpful. However, gardeners in much of the western United States will suffer this summer from hot days (sometimes record breaking) and will need to irrigate their gardens and trees in order for them to survive impending drought conditions. The ongoing drought has drained reservoirs and flows of rivers are down or, in some cases, dry entirely. Due to water scarcity, purveyors are restricting water use outside of homes and in some cases curtailing all landscape irrigation. Using water wisely in the landscape has never been more relevant than now. In this blog post we’ll continue to explore saving our gardens from drought and touch on water use, water demand and plant stress.

Good news — Bad news

The good news is that the longest day of the year was last month. That means that the days are ever so gradually getting shorter. As days shorten, plants use less water. Water use is tied directly to photosynthesis and when the lights are out there is no photosynthesis. Shorter days mean less demand for water. The bad news is that we may have record breaking hot days ahead. Plants become susceptible to wilt, sunburn and dieback during very hot weather. The best way to prevent this is to ensure that roots are moist during very hot weather.

Mediterranean Climate

It turns out that in Ventura, CA the longest day of the year is one of the historically driest months (least rainfall) and the shortest day occurs in a month with more rain than average. This is a classical Mediterranean climate, the rain falls when we least need it for thirsty plants. Plants may not use all the water that falls in winter but soil is leached of salts and deeper soil layers are filled with water. Large woody plants can utilize this deeper soil water in drier months.

Stress

What is not obvious is that stress, especially water stress, is not highest on the longest day but occurs and builds later in the summer and fall months. This is because water is slowly depleted from soils over time. Water use is compensated by irrigations during dry months so stress may not build depending on the effective use of irrigation to keep plants hydrated. Plants and gardens that are less reliant on irrigation build stress over time CUMULATIVELY until they are irrigated or rain falls again. So after the spring rains stop, the “stress clock” starts ticking and keeps building until rain or irrigation happens again in the fall or winter. It is no wonder that symptoms of stress such as wilt, sun burnt leaves, leaf fall and plant death occur in late summer when cumulative stress levels overcome plant physiological limits. Late summer often is the time when the hottest days occur and heat stress in addition to drought stress adds to the struggle for garden plants.

Save your plants in the fall from deadly stress

In the late summer or fall months plants are most likely to die of drought induced stress. This can be forestalled by irrigation applied in August which will reset the stress clock to lower levels. Stress won’t return to low wintertime levels because irrigation water is often of less quality than rain water. The salts in the irrigation water raise the osmotic potential of soil water creating another kind of stress. When it rains, these salts are washed from soil and plants are at their lowest stress levels.

Monsoons (see recent blog by Pam Knox) provide arid climates with stress relief when plants growing in hot deserts most need it. Many plants come out of dormancy or germinate only after the onset of summer rains. While monsoonal moisture can be unpredictable usually some rain falls in the desert southwest. In years when the monsoons don’t come or provide only low amounts of water, some trees or other woody plants even cacti, may die from stress.

Monitor your plants for stress as long dry periods or hot weather get longer and hotter. Apply water strategically to take off stress. Irrigate deeply by soaking the root ball(s) of the plant(s) you want to save. Established plants are pretty tough and can survive adverse periods, newly planted specimens not so much. They must be irrigated frequently just like they were in the nursery until their roots are will grown into site soils. For those of us living in a Mediterranean or monsoon climate we should wait until the onset of a wet period is near before installing new plants.

This Independence Day weekend blog post is about John Bartram, the American gardener and botanist who revolutionized gardening.

John Bartram was born a third generation Quaker on a farm in Darby, Pennsylvania on March 23, 1699. While he had no formal education beyond the local school, he was interested in medicine and medicinal plants. Stymied by the lack of local medical schools, his interests gradually turned to botany and he became one of the first practicing Linnaean botanists in North America.

In 1728, Bartram purchased 102 acres of farmland and 10.5 acres of marshland along the Tidal Schuylkill River from Swedish settlers. After establishing his farm and building his house, he laid out his first garden across six or seven acres on a terraced slope leading from the house to the river. His farm and collections expanded over time and have since been recognized as the first botanical garden in the USA.

Bartram made many plant collecting trips, the first documented one to the “Jerseys and Schuykill mountains” in 1735. His many travels by boat, horseback, and on foot, took him to New England, south to Florida, and west to Lake Ontario. While traveling he collected seeds and plant specimens, assessing how best to cultivate them back home in Philadelphia and how to share his discoveries. Other Colonial-era plant nerds supported his efforts and shared unique plants from their own collections.

Through his seed and plant sharing network Bartram became associated with Peter Collinson, an English merchant, fellow Quaker, and Royal Society member. Collinson, also a plant lover, shared seeds and plants with fellow gardeners, many well placed in British society.

Encouraged by Collinson, who eventually became his chief agent in London, Bartram established an international trade in North American seeds and plants packed carefully in wooden “Bartram’s Boxes” which were shipped in the fall. For five guineas, clients received a container of generally 100 or more varieties of seeds, as well as occasional dried plant specimens and other natural curiosities like bird nests and rocks. Despite the hazards of a sea voyage, many arrived safely to their destinations, where they established a new palette of American colors and shapes within European gardens and landscape.

Bartram’s nursery business continued to grow and thrive with sons William and John Jr. joining the business. Bartram and William continued their plant collecting journeys around North America. In October of 1765, after becoming lost on one of their trips near the Altamaha River in southeast Georgia, they came across the “rare and elegant flowering shrub” Franklinia alatamaha. Of course they collected specimens, which is fortunate for us as the plant appears to be extinct in its original native range. It survives today in cultivation because of the Bartrams’ efforts (you can read this interesting article for more on the topic).

After lobbying by Collinson and Benjamin Franklin in 1765, King George III granted Bartram a pension of £50 per year as the King’s Botanist for North America, a post he held until his death. In this position, Bartram shipped his seeds and plants to the royal collection at Kew Gardens. Bartram also contributed seeds to the Oxford and Edinburgh botanic gardens. In 1769 he was elected a foreign member of the Royal Swedish Academy of Sciences in Stockholm.

Bartram, the “Father of American Botany,” died in 1777. His sons, William and John Jr,. continued the family business of North American plants after the American Revolution. A total of three generations of the Bartram family continued to operate and expand the botanic garden. It was considered the major botanic garden in Philadelphia until the last Bartram heirs sold out in 1850. America’s oldest surviving botanic garden was dedicated as a 50 acre National Historic Landmark in 1963. Be sure to visit when you’re in the area.

Interested in learning more about John Bartram and other revolutionary gardeners of his time? There’s an excellent book by Andrea Wulf, “The Brother Gardeners“. I highly recommend it.

Happy Independence Day and here’s to garden revolutions everywhere!