Author: Lou DiToro

If you live in Rhode Island, your plants face many external threats, including destructive insects, devastating diseases, and harsh environmental conditions. Fortunately, your plants have an arsenal of natural defenses known as plant resistance. This complex system harnesses a plant’s natural mechanisms to create stronger, more resilient plants that can thrive in the harsh New England weather.

Threats that plants need to defend themselves against are pathogens, like bacteria and fungi, and viruses; pests, like insects, mites, and nematodes; and abiotic stresses, like drought, salinity, and nutrient deficiencies. Many plants have a complex set of mechanisms to resist these threats and boost a plant’s immune system.

The article below discusses plant resistance, provides tips on how to boost it in plants, and reviews some natural pest control methods for plants:

Understanding Plant Resistance

Understanding plant resistance offers many benefits that impact agriculture and gardening and promote a better understanding of the natural world. These benefits include:

• Increased agricultural productivity  
• Reduced reliance on pesticides
• Improved food security
• Increased plant growth/stress tolerance
• Enhanced development of disease-resistant plants

Knowledge of plant resistance also offers valuable insights into the complex world of plant interactions and their biology while boosting our appreciation for biological systems.

Boosting Plant Resistance: 7 Tips

Here are some tips to boost plant resistance. They’ll also optimize plant health, enhance soil conditions, create a favorable environment, and minimize stress factors that can help weaken plants, such as sudden temperature changes or transplanting shock:

• Balanced Nutrition: Ensure your plants receive a well-balanced fertilizer that provides all the essential nutrients, including phosphorus, potassium, manganese, zinc, boron, and silicon. 

• Proper Watering: Avoid over-watering or under-watering your plants. Aim for consistent moisture levels suitable for the specific plant type.

• Sunlight Requirements: Provide adequate sunlight as per the plant’s needs. Insufficient light can weaken plants and make them more susceptible to disease.

• Composting: Regularly add compost to your soil. Compost improves soil fertility, aeration, and drainage, promoting healthy root growth and fostering beneficial microbes that suppress pathogens.

• Mulching: Create a layer of mulch around your plants. Mulch helps retain moisture, regulate soil temperature, and suppress weeds that compete with plants for resources.

• Air Circulation: Boost proper air circulation around your plants, especially indoors.

Stagnant air can create ideal conditions for fungal diseases.

• Hygiene: Regularly remove diseased leaves or plant debris to prevent the spread of pathogens. Clean your tools to avoid transferring diseases between plants.

In gardens, you should practice crop rotation, which disrupts the life cycle of pests and pathogens that may have targeted a specific crop last season.

You should also choose plant-resistant varieties when possible, explore natural pest control methods, prune your plants and trees regularly, and minimize stress factors that can weaken plants, such as sudden temperature changes or transplanting shock when you can.

Preventing Diseases is the Key

Prevention is the key to combating the devastating plant diseases out there. Creating a healthy ecosystem in your garden or yard and implementing natural pest control methods can help a plant resist pest pressures without resorting to harsh chemicals. Here are some of the top natural pest control methods that can help prevent plant diseases:

• Companion planting
• Crop rotation
• Physical barriers (floating row covers/netting)
• Insecticidal soap
• Neem oil spray
• Diatomaceous earth

You can also prevent plant diseases by creating a better environment for beneficial predators like ladybugs, lacewings, and minute pirate bugs. These predators are highly effective at combating plant diseases. Ladybugs, for example, are voracious eaters. They can quickly consume large numbers of aphids and other soft-bodied pests.

Boosting plant defenses with these natural methods can help you fend off threats that can devastate plants, including destructive insects, devastating diseases, and harsh environmental conditions. Taking a holistic approach to protecting plants, however, is critical. By combining the tips and strategies described above in a coordinated approach, you can boost your plant’s disease resistance and help it thrive long-term.

Major tree failures happen more than you think. When trees fail, they can pose significant risks to you, your property, and others. Various factors can trigger tree failures, raising questions about tree care, maintenance, and prevention strategies. If one of your trees fail, it can cost you big bucks to have it removed by a professional tree removal service.

Removing a tree in Rhode Island can run anywhere from a few hundred dollars to a few thousand. Key factors affecting the cost include:

• Tree size and type
• Tree health and condition
• Accessibility
• Permit requirements
• Stump removal
• Species
• Location

We can’t pinpoint a specific percentage of tree failure each year. But the last thing you want to do is remove a tree because of failure. Below are some major causes of tree failure and strategies for treating them

Major Causes of Tree Failure

Understanding the factors that cause major tree failure is imperative. It can help you not only save a mature tree but also help raise awareness for better tree care practices and promote the importance of these plants in our communities.

Below are seven causes of major tree failure and how to stop them from devastating a tree.

1. Diseases—Fungal diseases, bacterial diseases, viral diseases. They all can weaken a tree’s structure and cause failure. Plant diseases are often hard to detect and can be compounded by other factors, like root damage and unfavorable weather. 

Treatment: Early detection is critical. Identify the pest and choose the correct control method, such as insecticidal soap, neem oil, or biological controls.

• Pests—Insects and other pests can devastate a tree’s roots, leaves, and/or trunk, weakening its structure and boosting its disease susceptibility. Our website has a list of pests to help with identification.

Treatment: First, identify the pest. Then, choose the correct treatment—biological controls, neem oil, insecticidal soap, etc. You can also consult RI Tree on pests and their controls.

• Weather—The northeast can be harsh on plants. Severe weather events, like storms, high winds, lightning strikes, snow storms, and even excessive rain or drought, can cause major tree failure.

Treatment: Proper pruning keeps trees healthy and minimizes wind resistance, improving overall health. Also, inspect your trees after severe weather events for signs of damage and address a problem as soon as possible.

• Improper planting— Planting trees too deeply, in the wrong location, or using improper techniques can lead to root problems that can eventually cause failure.

Treatment—You can’t do much to fix a tree planted incorrectly. Learn from the mistake and make sure you plant future trees correctly to avoid future problems.

• Root damage—Overcoming this issue is a challenge. Construction, soil compaction, and other activities can damage a tree’s roots, compromising its stability and ability to absorb water and nutrients.

Treatment—Proper care, such as watering, fertilizing, and mulching, can help a tree compensate for some root damage. But it’s a hard problem to beat.

• Poor maintenance—Trees need regular care to stay healthy and strong. That’s no secret. Neglecting trees can lead to various problems that can eventually contribute to failure.

Treatment—Proper maintenance includes regular watering, pruning, mulching, and monitoring signs of disease or pest infestation.

• Age— As trees age, they become weaker and more susceptible to failure.

Treatment: While aging is inevitable, proper care can help extend the life of your tree. Remember that even with the best care, some trees will someday reach the end of their natural lifespan and need to be removed safely. See our blog post on preserving mature trees.

Tree Failures Can Cost You

Major tree failure happens all too often. When it occurs on your property, it can cost you big time. So, be mindful of the seven major causes of plant failure described above. In severe cases of tree failure, you should consult a certified arborist. If you have a tree you think is failing, you can also contact RITree for help.

Special note: Majestic trees like the American elm will be the focus of a lecture presented by RITree’s John Campanini on Thursday, April 4th, at 6:30 p.m. Hosted by the Burrillville Conservation Commission, the lecture will be given at the Jesse Smith Library, Harrisville, RI. It is free, and the public is invited to attend. 

Water is an obvious plant requirement, but so is oxygen. A tree uses oxygen below ground and above to boost its health and growth. The tree’s vascular systems can’t properly function without soil oxygen, and its roots can‘t absorb water. Plus, there are microbes and organisms underground that can help enhance a tree’s survival but need oxygen to do it. That’s where aeration helps.

Aerating around your trees helps them “breathe” fresh air. It boosts tree health and growth dramatically. Here are some additional benefits of aerating your soil:

1. Improves oxygen flow
2. Enhances water flow
3. Increases nutrient absorption
4. Strengthens root growth
5. Increases tree health

Spike aeration is the easiest way for home gardeners to aerate soil themselves. Grab a spiky tool, like a hand cultivator, metal rake, or pitchfork, and puncture the soil in a broad area around your tree. This effort makes the soil more porous so that oxygen can access the roots and water can drain more readily through the soil. Be careful not to stab surface roots with your tool!

Aerate around your trees once or twice a year, in the Spring and/or fall, and always follow up with mulch (You can find a great video on the website how to properly mulch). For mature trees starting to show their age, it’s best to aerate the soil, mulch a large area around the base, and then walk over the roots as little as possible. Mature trees tend to be even more vulnerable to soil compaction.

Lastly – be aware that a healthy-looking tree does not indicate your soil is fine! The negative impacts of soil compaction might not become visible in the canopy for several growing seasons. So be proactive and build aeration into your annual tree care routine.

Want more tips about keeping your trees healthy or planning to install new woody plants? Check out RI Tree Council’s other articles on tree care page or sign up for the next Tree Stewards course. Go to RITree.org for more information.

Do you “mulch” your trees and shrubs regularly? Mulching is a tree care activity we often overlook. But it’s more important than many people think. It delivers vital benefits to trees and shrubs that go way beyond making your yard look nice. Put simply, Mulching boosts a plant’s health and hardiness.

So when should you mulch your trees and shrubs? That depends on your goals and the climate in your area. Each season has its pros and cons. The key is knowing when the best time to mulch is for you. Springtime mulching, for example, stimulates root growth but may require re-mulching later on in the season.

Wintertime mulching, on the other hand, insulates roots from sudden cold snaps but can trap frost and damage roots in freezing temperatures. Ultimately, you want to mulch when it’s most beneficial to your trees and shrubs. Soil temperature, rainfall patterns, and tree health are all factors when deciding when to mulch.

Benefits of Mulching

Mulching reduces water evaporation by 30-70%, increases water filtration 3 to 5 times, and lowers soil temperature by as much as 10° F. It also reduces weed pressure by 50-90%, boosts tree growth by 20-50, and deters pests from attacking trees and shrubs. If you use organic materials, it adds vital nutrients to the soil when the material breaks down, enriching the soil and boosting plant growth.

Mulching also:

• Prevents soil compaction from foot traffic and lawnmowers  
• Promotes better root penetration and aeration
• Prevents soil erosion from wind and rain
• Protects a tree or a shrub’s base
• Reduces the need to mow or weed around your trees
• Saves maintenance time, cost, and effort. 

These benefits can make a difference to your trees and shrubs—no doubt about it. But you need to choose the right mulch to enjoy those benefits. Organic mulch, such as wood chips, tree bark, and shredded leaves, offers advantages inorganic mulch doesn’t offer as discussed above. Inorganic mulch, such as gravel, rubber mulch, and fabric, can suppress weeds effectively but doesn’t deliver organic mulch’s nutrient benefits.

Tips on Mulching

There’s more to mulching than many people think. Here are some tips on how to mulch effectively:

• Mulch when it’s best for your trees and shrubs. Early spring (after the last frost) or late fall are generally ideal because soil temperatures are mild. Avoid mulching when it’s hot and dry, or the ground is frozen.  

• Start by removing any weeds or debris around the plant’s base, then identify your drip line—the outermost edge of the plant’s canopy. Spread the mulch to at least this edge but at least three to five feet from the trunk.

• Apply a 2 to 3-inch layer of organic mulch for mature trees and a 1 to 2-inch layer for young and new trees. Leave a gap between 2 to 3 inches from the tree trunk or shrub base. Avoid applying mulch too high. It can choke the choke the roots.

• Create a clean border around the mulch using either bricks, stone, or other edging material, which prevents the mulch from spreading and helps maintain a nice appearance.

• Replenish the mulch layer as it decomposes, or the wind blows it away. The mulch won’t suppress all your weeds, so you may still have to pull some from the ground. Pull them gently to avoid disturbing the mulch. it

• Check the soil under the mulch during dry periods. If it feels dry, water it deeply. You want to make sure the water gets to all the roots.

Apply these tips to mulch in a way that’s designed to boost your tree’s and shrub’s health and hardiness. Also, be mindful of nearby structures and walkways when mulching. It can attract pests.

Also, consider using different types of mulch for different areas of your yard. And don’t use fresh or dyed wood chips. They can release harmful chemicals. Mulching regularly can help your trees and shrubs thrive for years to come.