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As spring transitions into early summer, May emerges as one of the most strategic times to prune your plants. This critical window of opportunity can significantly influence the health, growth, and productivity of your garden throughout the warmer months and beyond. Understanding why May pruning matters and how to execute it properly can transform your landscape from ordinary to extraordinary.
Why May Is a Prime Pruning Window
May represents a unique intersection in the gardening calendar. The threat of hard frosts has typically passed in most regions, plants are actively growing, and you can clearly see which branches survived winter and which didn't. This timing allows you to make informed decisions about what to remove and what to keep.
Summer pruning is used primarily to control plant size, as plants store food for the following year during this period, so less food is available to promote growth compared to late-winter or early spring pruning. This makes May an ideal transition month where you can still stimulate vigorous growth while beginning to manage size and shape for the season ahead.
The warmer soil temperatures and longer days of May mean that plants respond quickly to pruning cuts. Wounds heal faster, and new growth emerges with vigor. This rapid response minimizes the risk of disease entering through pruning cuts and maximizes the plant's ability to redirect energy into productive growth.
The Science Behind Strategic May Pruning
Pruning in May helps to remove dead, damaged, or diseased branches, promoting better airflow and sunlight penetration throughout the plant canopy. Pruning helps open up the canopy, allowing sunlight and air to reach the inner parts of the plant, which supports overall health. This process reduces the risk of pests and diseases that often thrive in crowded, humid plant environments with poor air circulation.
Pruning removes dead, damaged, or diseased wood, preventing the spread of pests and diseases. By eliminating these problem areas early in the growing season, you give your plants a clean slate to work with. Dead wood serves as an entry point for pathogens and provides habitat for destructive insects, so removing it promptly protects the entire plant.
The physiological response to pruning is equally important. When you remove the growing tip of a branch, you eliminate apical dominance—the phenomenon where the terminal bud suppresses the growth of lateral buds below it. This stimulates dormant buds along the remaining stem to break and produce new shoots, resulting in bushier, fuller growth.
Comprehensive Benefits of Early Summer Pruning
Stimulates Vigorous New Growth
Cutting back certain parts of your plants in May encourages new, vigorous growth that will flourish during summer. Most trees and shrubs benefit from pruning during their dormancy, typically in late winter or early spring, as this timing promotes vigorous growth as the growing season begins. While May is slightly later than the traditional dormant season, plants are still in their active growth phase and respond enthusiastically to pruning.
This new growth tends to be more productive than older wood for many plant species. Fresh shoots produce more flowers, larger leaves, and stronger stems that can better support the plant's structure throughout the season.
Enhances Flowering and Fruit Production
Proper pruning can dramatically increase blooms and fruit yields later in the season. Pruning encourages new growth and enhances flower and fruit production, with studies showing that well-pruned flowering shrubs can produce 30% more blooms than those left unchecked.
For summer-blooming plants, May pruning is particularly beneficial. In spring, we prune shrubs that bloom in summer, which is anything that blooms after late May, as these plants mostly bloom on new wood, or the current season's growth. By pruning before they set their flower buds, you encourage the development of more flowering shoots.
Maintains Attractive Plant Shape
Regular trimming in May helps keep plants looking attractive and manageable throughout the growing season. Regular pruning ensures plants grow into the desired shape, preventing them from becoming overgrown or unruly. This is especially important for foundation plantings, hedges, and specimen plants that serve as focal points in your landscape.
Shaping plants early in the season allows them to fill in evenly as they grow, rather than trying to correct an overgrown plant later when you'll have to remove significant amounts of leafy growth.
Improves Overall Plant Health
Beyond aesthetics, May pruning contributes to long-term plant vitality. Thinning involves selectively removing branches to improve airflow and allow deeper sunlight penetration into the plant, preventing overcrowding which can lead to disease or stunted growth. Better air circulation means leaves dry faster after rain or dew, reducing the conditions that favor fungal diseases like powdery mildew and black spot.
Increased light penetration ensures that interior leaves can photosynthesize effectively, contributing to the plant's overall energy production. This results in stronger, more resilient plants that can better withstand environmental stresses.
Essential Pruning Techniques for May Success
Use Sharp, Clean Tools
Ensure your pruning shears are clean and sharp to make precise cuts. Keeping your tools clean, sharp, and in good repair is necessary to avoid damaging the plants and making clean cuts that heal quickly. Dull blades crush plant tissue rather than cutting cleanly, creating ragged wounds that take longer to heal and are more susceptible to infection.
It is worth sterilising secateurs from time to time, particularly if you are removing diseased growth, as this helps prevent spreading infection from one plant to another. A simple wipe with rubbing alcohol between plants provides adequate sterilization for most home gardening situations.
Your pruning toolkit should include bypass hand pruners for stems up to three-quarters of an inch in diameter, loppers for larger branches, and a pruning saw for anything thicker than two inches. Each tool has its purpose, and using the right one makes the job easier and produces better results.
Know Your Plant's Specific Needs
Different plants have specific pruning needs, so research is essential before making cuts. Different plants have unique pruning requirements based on their growth habits, life cycles, and flowering times, with some plants best pruned in spring while others might need attention in the fall or right after flowering.
Understanding whether your plant blooms on old wood (last year's growth) or new wood (current season's growth) is crucial. Pruning a spring-blooming shrub that flowers on old wood in May means sacrificing this year's blooms, while pruning a summer bloomer that flowers on new wood will enhance its performance.
Remove Suckers and Water Sprouts
Suckers and water sprouts can divert energy from the main plant, weakening it overall. Suckers are vigorous shoots that emerge from the rootstock below the graft union on grafted plants, or from the roots of plants growing on their own roots. Water sprouts are equally vigorous vertical shoots that emerge from branches or the trunk.
Both types of growth are typically unproductive and can quickly dominate a plant if left unchecked. They grow rapidly but rarely produce flowers or fruit, instead channeling the plant's resources into vegetative growth. Remove them as close to their point of origin as possible.
Make Cuts at the Right Location
Make cuts just above a healthy bud or branch junction. Make a clean 45-degree cut on a downward slant, away from the bud, about a quarter inch above an outward facing bud, as cutting on an angle helps water run off and leaving 1/4 inch of cane above the bud ensures the wound can heal properly.
The angle of the cut matters because it directs water away from the bud, preventing moisture from pooling and potentially causing rot. The distance above the bud is equally important—too close and you risk damaging the bud, too far and you leave a stub that will die back and potentially harbor disease.
Always avoid cutting the branch collar when removing branches, as this can prevent proper healing. The branch collar is the slightly swollen area where a branch meets the trunk or a larger branch. This tissue contains cells that rapidly seal the wound, so preserving it is essential for proper healing.
Follow the One-Third Rule
As a good rule of thumb, do not remove more than 30% of the plant at any one time. Removing too much foliage at once severely stresses the plant by eliminating its food-producing capacity. The one-third rule provides a safe guideline that allows you to make significant improvements while keeping the plant healthy.
For severely overgrown plants, consider a gradual rejuvenation approach spread over two or three years rather than attempting to correct everything in a single season.
Plants That Thrive with May Pruning
Roses
Roses benefit tremendously from attention in May, though the specific approach varies by type. Roses should be pruned annually in spring to encourage new growth and a succession of flowers throughout the growing season.
For repeat-blooming roses like hybrid teas, floribundas, and grandifloras, May pruning focuses on removing any winter-damaged wood that wasn't apparent earlier and shaping the plant. Moderately prune to 24-36 inches tall in the spring and deadhead during the growing season to promote rebloom.
Climbing roses require a different approach. Climbing roses should have older canes thinned out in April or May, leaving only younger branches that produce the best flowers. This maintains the plant's vigor while ensuring abundant blooms on the most productive wood.
Shrub roses and landscape roses are more forgiving. Many modern varieties are bred for easy care and don't require the precise pruning that hybrid teas demand. A general cleanup and shaping in May sets them up for months of continuous blooming.
Summer-Flowering Shrubs
Shrubs that flower in summer, such as crape myrtle, buddleia, and althea, should be pruned in late winter or early spring. If you missed the earlier window, early May still works for these plants in most regions.
Butterfly bush (Buddleia) is particularly responsive to pruning. Some summer bloomers like butterfly bush, caryopteris, and beautyberry do best when coppiced, or cut completely to the ground. This severe pruning stimulates vigorous new growth that produces abundant flowers throughout summer and fall.
Other summer bloomers like hydrangeas require more nuanced approaches depending on the species. Panicle hydrangeas (H. paniculata) and smooth hydrangeas (H. arborescens) bloom on new wood and can be pruned in spring, while bigleaf hydrangeas (H. macrophylla) bloom on old wood and should only receive light pruning to remove dead wood.
Fruit Trees
May offers a final opportunity for fruit tree pruning in many regions, though earlier pruning is generally preferred. Removing dead, diseased, or damaged branches can help keep the canopy healthy, and pruning fruit trees in spring rewards you with a better harvest later in the season, though remember to prune apples, pears, and figs, but not stone fruits.
Stone fruits like cherries, plums, peaches, and apricots should not be pruned in spring due to their susceptibility to diseases that spread during wet weather. These are better pruned in summer when conditions are drier.
For apple and pear trees, May pruning focuses on removing water sprouts, thinning crowded branches, and maintaining the tree's structure. Proper pruning improves fruit size and quality by ensuring adequate light reaches all parts of the canopy and by preventing branches from becoming overloaded with fruit.
Deciduous Shrubs
Many deciduous shrubs benefit from May attention, particularly those grown primarily for foliage rather than flowers. These can be shaped and sized without concern about removing flower buds.
Spring-flowering shrubs like lilacs, forsythia, and azaleas should be pruned immediately after flowering if needed. Spring is the ideal time to cut back spring flowering shrubs, as these plants set their flower buds in the previous year, so pruning immediately after flowering encourages robust growth and abundant blooms for the following year.
If you prune these plants in May before they bloom, you'll sacrifice this year's flowers. However, if they've already finished blooming by May in your region, it's the perfect time to shape them and control their size.
Perennials
May is an excellent time for perennial maintenance. Early-blooming perennials that have finished flowering can be deadheaded or cut back to encourage rebloom or tidier foliage. Deadheading involves removing spent flowers, and snipping away these faded blooms lets the plant redirect its energy toward producing new ones.
Perennials that tend to flop or become leggy, such as tall sedums, asters, and mums, can be pinched back in May to promote bushier growth and sturdier stems. Removing the top few inches of growth encourages branching, resulting in more compact plants with more flower buds.
Vines and Climbers
Grapevines benefit from May attention in the form of shoot thinning and positioning. Grapes produce fruit on one-year-old wood, so your goal is to maintain a good balance of new and old wood each season. May is when you can see which shoots are most vigorous and position them properly on your trellis system.
Other vigorous vines like wisteria, clematis, and climbing hydrangea may need pruning to control their size and direct their growth. The specific timing depends on when they bloom, but May often works well for managing their exuberant growth.
Evergreen Shrubs
During this peak growing season, plants such as privet, boxwood, and holly require trimming to prevent them from becoming too large or unmanageable, with regular hedging helping maintain a controlled, intentional look.
Broadleaf evergreens like boxwood, holly, and privet respond well to May pruning. They're actively growing and will quickly fill in any gaps created by your cuts. This is an ideal time to shape hedges and maintain the formal appearance of foundation plantings.
Needled evergreens require more caution. Most can be lightly pruned in May, but you must stay within the green, actively growing wood. Cutting back into old, brown wood on most conifers results in bare spots that never fill in, as these plants lack the ability to produce new growth from old wood.
Advanced Pruning Strategies for May
Thinning vs. Heading Cuts
There are several techniques employed in pruning, such as thinning, heading back, pinching, and shearing, with thinning removing entire branches or limbs to improve the plant structure and allow light and air to penetrate the canopy.
Thinning cuts remove entire branches back to their point of origin, whether that's the trunk, a larger branch, or the ground. These cuts open up the plant's interior without stimulating excessive new growth. They're ideal for maintaining natural form and improving air circulation.
Heading cuts remove only part of a branch, cutting back to a bud or side branch. These cuts stimulate vigorous growth below the cut, making them useful when you want to encourage bushiness or redirect growth. However, overuse of heading cuts can result in dense, twiggy growth that requires constant maintenance.
Rejuvenation Pruning
For severely overgrown or neglected shrubs, May can be an appropriate time for rejuvenation pruning. Drastic rejuvenation pruning involves making all cuts in the dormant season, cutting all wood back to 6-10 inches, and this technique requires follow-up pruning in midsummer to control new growth.
A more moderate approach spreads the rejuvenation over three years. Moderate or gradual rejuvenation pruning is usually done over a 3-year period, with one-third of the top growth cut back each year, for example, if the shrub has 9 main branches, one would cut 3 the 1st year, 3 more the 2nd year, and the remaining 3 the 3rd year.
This gradual approach is less shocking to the plant and maintains some ornamental value throughout the process. It's particularly useful for large, mature shrubs that would look stark if cut back all at once.
Pinching and Deadheading
Pinching involves removing just the growing tip of a stem, usually with your fingers rather than pruning shears. This gentle form of pruning is perfect for herbaceous perennials and annuals in May. It encourages branching without removing significant plant material.
Deadheading—removing spent flowers—serves multiple purposes. It improves appearance, prevents seed formation (which can drain plant energy), and often encourages additional blooming. For many perennials and repeat-blooming shrubs, regular deadheading throughout the growing season significantly extends the flowering period.
Hedge Maintenance
The shape of the hedge is very important and all hedges need to be wider at the bottom than the top, as this is true for both formal and informal types, with the triangular shape helping to expose more of the plant to light and eliminating sparse, twiggy growth at the base.
May is an excellent time for the first hedge trimming of the season. The plants are growing vigorously and will quickly fill in, creating a dense, uniform appearance. For formal hedges, plan on multiple trimmings throughout the growing season to maintain crisp lines.
Informal or natural hedges require less frequent attention but still benefit from May pruning to control size and remove any winter damage. These hedges maintain a softer, more naturalistic appearance while still providing screening and structure.
Common Pruning Mistakes to Avoid
Over-Pruning
One of the most common mistakes in pruning is over-pruning, as removing too much at once can stress a plant and diminish its vigor. It's tempting to get carried away once you start cutting, but restraint is important. Step back frequently to assess your progress and avoid removing more than necessary.
Over-pruned plants often respond by producing excessive water sprouts and suckers as they attempt to replace the lost foliage. This creates more work for you and results in weak, unproductive growth.
Topping Trees
Another mistake is "topping" trees—cutting off the tops of the trees indiscriminately, which can lead to weak new growth and increased risk of disease. Topping destroys a tree's natural form, creates large wounds that are slow to heal, and stimulates the growth of numerous weak shoots that are poorly attached and prone to breaking.
If a tree has grown too large for its location, proper crown reduction by a certified arborist is a much better solution than topping. Better yet, choose appropriately sized trees for each location in your landscape.
Pruning at the Wrong Time
Pruning at the wrong time can stress plants, limit blooms, and increase susceptibility to disease, while pruning at the wrong time can lead to stunted growth, reduced blooms, and vulnerability to pests or disease.
While May is excellent for many plants, it's disastrous for others. Spring-blooming shrubs pruned in May lose their flowers. Oak trees pruned in spring risk oak wilt infection. Stone fruit trees pruned in wet weather become susceptible to bacterial and fungal diseases.
Using Dull or Dirty Tools
Dull tools crush and tear plant tissue rather than making clean cuts. These ragged wounds take longer to heal and provide entry points for pathogens. Similarly, dirty tools can transfer diseases from one plant to another, spreading problems throughout your garden.
Take a few minutes to sharpen your tools before each pruning session and wipe them with alcohol between plants, especially when working with diseased material.
Leaving Stubs or Cutting Too Close
Leaving long stubs above buds or branch collars creates dead wood that must be pruned again later. These stubs often die back unevenly and can harbor pests and diseases. Conversely, cutting too close to a bud can damage it, preventing new growth from emerging.
The goal is to make cuts that the plant can seal quickly and efficiently, minimizing the time that wounds remain open and vulnerable.
Creating a May Pruning Schedule
Early May Tasks
Begin the month by assessing winter damage and removing any dead or diseased wood throughout your landscape. This cleanup work improves appearance and plant health regardless of species or bloom time.
Early May is also the time to prune summer-blooming shrubs if you haven't already done so. The earlier in the month you complete this task, the more time plants have to produce flowering shoots before their bloom period.
Mid-May Priorities
As spring-blooming shrubs finish flowering, prune them to control size and shape. This is your window to work on forsythia, lilacs, azaleas, and other early bloomers without sacrificing next year's flowers.
Mid-May is also ideal for shaping evergreen shrubs and hedges. They're growing actively and will quickly recover from pruning, filling in to create dense, attractive forms.
Late May Maintenance
By late May, focus shifts to pinching and deadheading perennials and annuals. Remove spent flowers from early-blooming perennials to encourage rebloom and prevent self-seeding where unwanted.
This is also the time to thin fruit on fruit trees if they've set a heavy crop. Removing excess fruitlets when they're small allows the remaining fruit to grow larger and prevents branch breakage from overloading.
Post-Pruning Care for Optimal Results
Cleanup and Sanitation
After pruning, thoroughly clean up all debris from around your plants. Fallen leaves, twigs, and pruned branches can harbor pests and diseases that will reinfect your plants. Dispose of diseased material in the trash rather than composting it, as home compost piles rarely get hot enough to kill all pathogens.
Clean and oil your pruning tools before storing them. This prevents rust and keeps them ready for the next use. Sharpen blades as needed so they're always ready to make clean cuts.
Watering and Fertilizing
Pruned plants benefit from consistent moisture as they recover and produce new growth. Water deeply and regularly, especially during dry spells. Adequate moisture helps plants seal wounds and supports the rapid growth of new shoots.
A light application of balanced fertilizer after pruning provides nutrients for new growth. Avoid heavy fertilization, which can stimulate excessive soft growth that's vulnerable to pests and diseases. A slow-release formulation provides steady nutrition throughout the growing season.
Mulching
Refresh mulch around pruned plants to conserve moisture, moderate soil temperature, and suppress weeds. A 2-3 inch layer of organic mulch provides these benefits while gradually improving soil quality as it decomposes.
Keep mulch a few inches away from plant stems and trunks to prevent moisture-related problems and discourage rodents from nesting against the plants.
Monitoring and Follow-Up
Check pruned plants regularly for signs of stress, disease, or pest problems. Early detection allows you to address issues before they become serious. Look for wilting, discoloration, unusual growth patterns, or insect activity.
Some plants may require follow-up pruning later in the season. Water sprouts and suckers often emerge after heavy pruning and should be removed promptly. Fast-growing hedges may need additional trimming to maintain their shape.
Regional Considerations for May Pruning
Cold Climate Adjustments
In northern regions where spring arrives late, early May may still be too early for some pruning tasks. Wait until the threat of hard frost has passed and plants are actively growing before pruning tender species.
Cold climate gardeners should be particularly cautious about pruning marginally hardy plants too early. A late frost after pruning can damage new growth and set plants back significantly.
Warm Climate Timing
In southern regions, May may be late for some pruning tasks that are better completed in March or April. However, it's still appropriate for summer-blooming plants and for maintenance pruning of evergreens and hedges.
Warm climate gardeners should be mindful of approaching summer heat. Pruning too late in spring can stress plants just as they're facing hot, dry conditions. Complete major pruning early enough that plants can recover before heat stress becomes a factor.
Coastal and Mild Climate Flexibility
Gardeners in mild, coastal climates often have the most flexibility with pruning timing. The absence of hard frosts and moderate temperatures throughout the year mean that many plants can be pruned over an extended period without risk.
However, this flexibility shouldn't lead to complacency. Even in mild climates, pruning at the optimal time for each species produces the best results.
Tools and Equipment for Successful May Pruning
Essential Hand Tools
Bypass hand pruners are the workhorse of the pruning toolkit. Choose quality pruners that fit your hand comfortably and can be easily sharpened. Bypass pruners make cleaner cuts than anvil-style pruners and are better for living wood.
Loppers extend your reach and cutting power for branches up to two inches in diameter. Look for models with compound action or ratcheting mechanisms that multiply your cutting force, making it easier to cut through thick branches.
A pruning saw handles branches too large for loppers. Folding saws are convenient and safe to carry, while fixed-blade saws often cut faster. Choose a saw with aggressive teeth designed for green wood rather than a carpentry saw.
Protective Gear
Heavy-duty gloves protect your hands from thorns, rough bark, and blisters. Rose gloves with extended cuffs that cover your forearms provide extra protection when working with thorny plants.
Safety glasses shield your eyes from flying debris and branches. This is especially important when working overhead or in dense, twiggy growth where branches can snap back unexpectedly.
Long sleeves and pants protect your skin from scratches and sun exposure. Choose lightweight, breathable fabrics for comfort during May's warmer temperatures.
Maintenance Supplies
Keep a sharpening stone or file handy to touch up blade edges during extended pruning sessions. Sharp tools make the work easier and produce better results.
Rubbing alcohol or a dilute bleach solution (one part bleach to nine parts water) provides quick sterilization between plants. Carry a small spray bottle or container of wipes for convenient access.
Lubricating oil prevents rust and keeps moving parts operating smoothly. A light application after cleaning and before storage extends tool life significantly.
Environmental Benefits of Proper Pruning
Supporting Beneficial Wildlife
Well-pruned plants create better habitat for beneficial insects and wildlife. By maintaining plant health through pruning, you enhance habitats for beneficial wildlife and insects that contribute to a balanced ecosystem.
Dense, healthy foliage provides nesting sites for birds and shelter for beneficial insects. Proper pruning maintains this habitat value while preventing plants from becoming so overgrown that they're difficult to manage.
Reducing Pesticide Needs
Healthy, well-pruned plants are more resistant to pests and diseases, reducing the need for chemical interventions. Good air circulation and light penetration—both results of proper pruning—create conditions that discourage many common plant problems.
When you do encounter pest or disease issues, they're easier to spot and treat on well-maintained plants. Early detection and targeted treatment are more effective and environmentally friendly than broad-spectrum applications.
Water Conservation
Properly sized plants that fit their space require less water than overgrown specimens. Pruning helps maintain appropriate plant size, reducing water needs and supporting conservation efforts.
Additionally, plants with good structure and healthy root systems use water more efficiently. The improved vigor that results from proper pruning translates to better drought tolerance.
Long-Term Planning and Plant Selection
Right Plant, Right Place
While pruning is an essential maintenance task, the best way to minimize pruning needs is to choose plants that naturally fit their intended space. A plant that matures at the desired size requires only light maintenance pruning rather than constant cutting back.
Before adding new plants to your landscape, research their mature size and growth rate. Consider not just height but also width and overall form. A plant that naturally grows into the shape you want requires far less intervention than one that must be constantly pruned to maintain an unnatural form.
Developing a Pruning Rotation
Create a pruning calendar that accounts for all the plants in your landscape and their specific needs. This ensures that nothing gets overlooked and that you're pruning each plant at the optimal time.
A written schedule is particularly helpful for large properties or diverse plant collections. Note when each plant should be pruned, what type of pruning it needs, and any special considerations. Review and update this schedule annually based on your observations and results.
Learning from Experience
Keep notes on your pruning activities and their results. Record what you pruned, when you did it, and how the plants responded. Over time, this information helps you refine your techniques and timing for your specific conditions.
Don't be afraid to experiment within reason. A cut made in the wrong place, or a shrub reduced a little more than intended, is rarely anything more than a short-term setback, as with time and spring growth, the rose will recover quickly. This principle applies to most plants—they're remarkably resilient and forgiving of minor pruning mistakes.
Conclusion: Setting the Stage for Summer Success
By understanding the timing and techniques of pruning in May, gardeners can set the stage for a healthy, vibrant summer garden. This critical month offers unique opportunities to shape your landscape, promote vigorous growth, and enhance flowering and fruiting.
Proper care now—removing dead and diseased wood, improving air circulation, stimulating new growth, and maintaining attractive forms—leads to beautiful blooms, abundant fruits, and healthy plants in the months ahead. The investment of time and effort in May pays dividends throughout the growing season and beyond.
Whether you're working with roses, fruit trees, flowering shrubs, or perennials, May pruning helps your plants reach their full potential. Armed with sharp tools, knowledge of plant-specific needs, and proper techniques, you can confidently approach this essential garden task.
Remember that pruning is as much art as science. While guidelines and best practices provide a framework, your observations and experience with your specific plants and conditions will ultimately guide your decisions. Pay attention to how your plants respond, adjust your approach as needed, and enjoy the process of nurturing your garden to peak performance.
For more detailed information on specific pruning techniques, visit the Oregon State University Extension Service or consult your local extension office for region-specific guidance. The Royal Horticultural Society also offers comprehensive pruning guides for a wide variety of plants.
With thoughtful May pruning, you're not just maintaining your garden—you're actively shaping its future, promoting health and beauty that will be evident throughout the summer and for years to come.