Once mid-late spring rolls around, you may notice that some of your landscape plants are in need of some tender loving care. After the lack of snow in some parts of the northeast and prolonged frigid temperatures in the single digits this past winter season, certain plants have been more affected than others by the lack of insulation from snow cover and extreme cold. Another factor affecting the vitality of your plants could the abundant rainfall amounts hitting the eastern seaboard.
Birch trees are one species that the winter has especially taken a toll on. By this time in June, Birch trees should have pushed out most of their new foliage, but you may notice some bare branches and empty spots on your tree. If that is the case, gently scrape the bark or cut a tip off bare stems to see if there is any sign of green. If the cambium growing layer underneath the bark is green, give the tree a little more time to see if it will push out any new growth from those branches. If the layer below the bark is brown, remove the dead branch from the tree to help direct growing energy to where it is needed. Give the tree a good feeding (preferably a deep root application) and some time. The tree should gradually show signs of recovery and continue to regain its health.
Boxwood is another plant which has been affected by the recent weather abnormalities. If your boxwood is looking a little paler than usual with some yellowing in the leaves, it could be a sign of iron deficiency. The abundance of rain here in the northeast has literally “washed” away much of the iron in the soil. Iron chlorosis can develop under conditions that reduce the availability of iron to the plant, such as a combination of cooler than normal temperatures and poor root aeration or soil drainage due to constant moisture. To remedy the lack of iron, apply a liquid iron solution to the soil around your plants. Most supplements will work over time to restore the plant back to good health.
Hydrangea are another plant showing signs of winter damage over the past several years here in the northeast and over other parts of the country. If your Hydrangea is still showing bare stalks above new growth now in June, and stems appear dead, simply prune off the damaged wood to beneath the line of new foliage. As with most flowering plants, application of a plant food that is high in phosphorus in mid-late spring will encourage buds.
Routinely checking your garden in springtime can catch early signs of plant distress and help in avoiding more serious issues down the road. During springtime and throughout the ongoing growing season, early detection of plant issues is a worthwhile practice, After all, a little preventive care can go a long way!
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The Spotted Lanternfly (Lycorma delicatula) is a new invasive insect that is native to China, Bangladesh and Vietnam, and introduced to Japan and Korea where it has become a major pest of grapes. Spotted Lanternfly primarily feeds on tree of heaven (Ailanthus altissima) but can also feed on a wide variety of plants such as grapevine, hops, maple, walnut and fruit trees, which has posed a great threat to these industries. This invasive pest was first discovered in Pennsylvania in 2014 and has since been found in New Jersey, Delaware and Virginia. In New York. A dead insect was found in Delaware County in the fall of 2017. In 2018, insects were reported in Albany, Monroe, Yates and Suffolk counties. Following these reports, the DEC and Department of Agriculture and Markets immediately began extensive surveys throughout the area. At this time, no additional insects have been found.
The Spotted Lanternfly adult is approximately 1 inch long and 1/2 inch wide at rest. Immature stages are black with white spots and develop red patches as they grow to maturity. Nymphs are black with white spots that turn red before transitioning into adults. Spotted Lanternfly can be seen as early as April and adults begin to appear in July. Their forewings are grayish with black spots. The lower portions of their hindwings are red with black spots and the upper portions are dark with a white stripe. In the fall, adults lay 1-inch-long egg masses, which when first laid are are smooth and brownish-gray with a shiny, waxy coating. Older egg masses appear as rows of 30 to 50 brownish seed-like deposits in 4 to 7 columns on the trunk, roughly an inch long. Spotted Lanternfly is capable of jumping and flying short distances and is spread primarily through human activity. They can spread to new areas when they lay their eggs on vehicles, firewood, outdoor furniture and stone.
Attacked trees will develop weeping wounds which appear wet, while leaving a greyish or black trail along the trunk. The sap may give off a fermented odor and will attract other insects to feed, notably wasps and ants. To destroy egg masses, scrape them off, place them into alcohol or hand sanitizer and double bag. It is important to collect specimens of any life stage and report sightings of egg masses, nymphs, or adult spotted lanternfly to your local DEC or Cooperative Extension for further verification.
Plans are in place for the detection and prevention of Spotted Lanternfly in the New York area. Extensive trapping surveys will be conducted in high-risk areas throughout the state as well as inspections of nursery stock, stone shipments and commercial transports from infected areas. The DEC and partner organizations encourage everyone to be on the lookout for this pest.
Sources: Pennsylvania State University Cooperative Extension and NY State Department of Environmental Conservation
Fall is approaching and a common garden pest, the fall webworm (Hyphantria cunea) can become noticeable on trees, causing unsightly larval nests covering entire branches, resulting in stress to the tree and severe leaf damage. Fall webworm are caterpillars that weave loose webbing around the tree’s outer foliage while feeding on leaves, compared to tent caterpillars that appear in spring and build their more opaque nests within the inner crotch of the branches. The webworm caterpillar is approximately one inch in length with a light greenish-yellow body and black to reddish head. Adults emerge later on as white moths with dark spots on their wings.
The best way to eliminate fall webworm is to remove the infected branches immediately, before the larvae hatch and take over the tree. If the caterpillars have already left the nest, it is recommended to spray with an organophosphate insecticide such as Acephate (contained in Orthene or Sevin) or Malathion. Acephate is both a foliar and soil systemic which keeps on working 10–15 days after application. Malathion is a foliar insecticide which is also commonly used, but note that Malathion may leave a residue. The best proactive method of killing overwintering larvae is to apply a dormant oil in early spring while the tree is dormant. Dormant oil is a more natural solution and works by smothering and killing the overwintering eggs.
In the spring, adult moths emerge and deposit eggs, continuing the life cycle of the caterpillar. These caterpillars may go through as many as eleven growth stages before leaving the web.
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HISTORY: After may years of experimentation, Japanese horticulturist, Dr. Toichi Itoh, successfully created seven peony hybrids from a tree peony in 1948, which were known to became the first Itoh peonies. Itoh Peony are derived from a cross breeding between herbaceous and tree peonies, forming a stronger, longer blooming variety over its predecessors. Similar to tree peonies, members of this cultivar have large, long lasting blooms and strong stems that do not require staking. The deeply lobed dark green foliage on a 3-4 foot high by wide plant lasts all summer and into fall, making an attractive addition to the garden. Itoh peonies are also known to be more disease resistant and are not preferred by deer.
GROWING AND MAINTAINING: Itoh peonies prefer to be placed in full sun to partial shade in a rich, well-drained soil. Feed in spring with a low nitrogen fertilizer to promote blooms. Fertilization is not recommended in late summer to fall when the plant is going into dormancy. Once blooms have completed in late spring, Itoh peony can be deadheaded by removing spent flower stalks, leaving its attractive foliage to remain for the rest of the growing season. In autumn, once the foliage turns brown, cut back plants to about 4-6 inches up from the soil level. It is recommended to mulch around the plant to insulate the roots from freezing temperatures. Once spring comes around, your peony will emerge for another growing season. Itoh peony can also be divided in autumn as you would herbaceous peonies.
I discovered this wonderful peony a few years back and have enjoyed its beautiful, sturdy, and disease resistant blooms in the garden. You may find them to be a nice addition as well!
Ornamental Pear trees have been recently under attack from a hard to treat fungus known as Trellis rust. Originally from Europe, Trellis rust or European Pear Rust is caused by the rust fungus Gymnosporangium sabinae. The disease may present a serious health threat to members of the Pyrus species, including both ornamental and fruit pear types. Ornamental Pear trees have been popular trees planted for decades noted for their fast growth rate, tolerance of urban conditions, fairly compact shape and white blooms that appear in early spring. Unfortunately, hundreds of trees have been noted dying in Rockville Center and the disease has been spreading to the Nassau and Suffolk County areas of Long Island. The fungus has spread from the mid-western states to upstate New York and Connecticut over the past several years and seems to be getting progressively worse. According to horticulturists, part of the problem is that the trees have been over-planted, resulting in a rapid spreading of the disease.
Symptoms to look out for are yellow-orange leaf spots (see photograph), which develop into spores in late summer. The spores can be spread to other host plants by wind or to the roots if the trees are close enough together. The secondary host during the winter months is juniper, allowing the fungus to survive when the pear trees drop their leaves; hence, continuing the cycle in the spring.
If you spot damage on your tree, remove and destroy the infected leaves to prevent spores from spreading. If caught early enough, systemic and spray fungicides can be applied to inhibit the spread of the disease. Best preventive measures are to be alert in monitoring your trees, and when in doubt, call a tree professional.
What is “winter bronzing”? While approaching the end of winter, some of your favorite evergreens may appear to take on a bronze appearance. You may be wondering. “Is this normal or is my plant dying?” Changing foliage color is a normal phenomena that affects some evergreens near the end of winter while seasons are transitioning. Freezing temperatures, followed by a warming trend, longer hours of sunlight, then more cold can trigger foliage to discolor. The color change is a reaction to low temperatures, winds and sunlight, causing mild desiccation of the needles or leaves, allowing the underlying colors to show through. This dulling of green foliage is more pronounced on plants that receive more sunlight. The result is commonly known as “winter bronzing”. The longer the ground is frozen and the more water that is evaporated from the plant than it can take in, the more pronounced the foliage will appear to turn from green to brown, bronze, or even orange or purple. This process is similar to why deciduous leaves change color in the fall. While the tree is going dormant for the winter months, chlorophyll production subsides and the true underlying colors of the leaves are revealed. When can I expect my trees to look more normal? Once the temperatures rise and new growth is stimulated, the foliage will turn back to a more vibrant green. Broken or dead branches are different in that they are completely dried out and brown. Those branches should be pruned off the tree in late winter/early springtime to prevent any further damage. Any falling or divided tree leads can be arbor tied to secure them and encourage upright growth. Split branches can also be arbor tied together, and if caught in time the cambium growing layer of the tree can mend. In the photograph above, the center upright Western Arborvitae are displaying signs of bronzing with no evidence of any completely browned or broken branches, both indications of a normal and healthy tree.
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Have the temperatures been rising and are you yearning to go out into the garden? Spring is here and it is a time to start planning and prepping the garden for a successful start to the planting season. There are some recommended maintenance tips for getting your garden underway. Here is a list of common gardening tasks to be performed in late winter/early spring. (I recently posted this article on my other blog A Guide to Northeastern Gardening, but felt it was also fitting for here.)
True or False? Any dead material remaining from last year should be removed from your garden now. True. It is best practice to remove dead material from the garden in fall to prevent possible pests and disease in your garden. If you have left annuals or perhaps perennials for winter interest, now is the time to tend to them, along with any weeds that might have survived the winter. Pull out any dead remaining annuals and prune perennials back to the ground to encourage new growth. If cold temperatures are still to be expected, push mulch up around the crown of the plants to protect them from temperature fluctuations.
True or False? New mulching should be applied now before the ground thaws.False. Mulch acts as an insulator and applying mulch before thawing would actually inhibit warming as temperatures rise. Allow the soil to warm, then apply two to four inches of natural pine mulch. When applying, keep mulch several inches away from tree and shrub trunks to prevent oxygen loss and rotting. Mulch benefits plants by reducing water evaporation, preventing weeds, adding organic matter to the soil and also acts as a buffer, preventing drastic changes in soil temperatures.
True or False? Nitrogen based lawn fertilizer can only be applied after April 1st. True. According to the EPA, the prohibition on application of fertilizer between December 1st and April 1st applies to products that contain nitrogen (N), phosphorus (P), or potassium (K). If a product does not contain any of these nutrients, it could be applied during the winter months without violating this law. Explanation: If the ground is frozen, there is a greater danger of runoff and possible contamination of groundwater. Fertilizers applied when the ground is thawed and porous are absorbed and utilized by plant material and go through a natural filtration process before reaching the aquifer system. Please note that there are a variety of organic, natural fertilizers on the market that are more environmentally friendly. Success rate depends on brand and application.
True or False? Spring flowering trees and shrubs should be pruned in late winter/early spring. False. General rule of thumb is to prune flowering plants AFTER they flower. Early spring flowering trees and shrubs including rhododendron, azalea, forthysia, magnolia, plum, Eastern Redbud and cherry form their buds from the season before and should be not be pruned until after flowering. Pruning them now will remove flower buds that have already formed, resulting in a loss of blooms.
True or False? Summer blooming shrubs such as Spirea and Buddleia should be pruned in spring. True. Mid and late summer flowering shrubs such as Spirea and Buddleia (butterfly bush) prefer a spring pruning to promote fullness and blooms. Prune Spirea slightly for shaping. If the plant is overgrown to the point it is unsightly, it can be pruned more drastically to rejuvenate it now in spring. Buddleia benefits from an early spring pruning and should be pruned all the way back in late winter/early spring to promote fuller plants and better blooms in late summer. This practice is best performed once you see signs of life on your plants.
True or False? The best time to prune evergreens is in early spring. True. Evergreens can be pruned anytime when there is no threat of extreme temperature changes that would cause undue stress; however, the best time is either in early spring before they push out new growth, or afterwards once new candles form. When pruning evergreens that form candles, such as white pine, it is best to cut candles in half to keep the plant more compact.
True or False? Liriope and grasses should be cut back and divided now in spring. True. Liriope and ornamental grasses can be cold sensitive. Exposing the crown of the plant could be the reason for snow and cold damage. It is best to leave liriope and grasses alone in fall and to prune them back in early spring to allow for new growth. Spring is also the time to divide and move other perennials that have become overgrown. It is recommended that most perennials be divided every four years for best bloom. Dig up and divide with a sharp clean spade just as new growth appears, replant and add a sprinkle of slow release plant food in with the soil to help root promotion. Water in thoroughly.
True or False? Knock Out Roses should be pruned back in early spring. True. Wait until your roses are sprouting new shoots and showing some signs of life. Then, prune off dead wood or overgrown branches back about one third the size of the plant to promote strong growth and blooms. Be careful to watch while pruning so that you achieve a nice rounded shape for your plant. Early spring is also a good time to apply an organic slow release rose fertilizer mixed in with the soil at the base of the plant to ensure a successful start to the growing season. I would also recommend a regular watering schedule from the base of the plant, since roses do not fair well with constant water on their foliage.
True or False? Summer blooming bulbs should be planted in late spring. True. While spring blooming bulbs such as crocus, hyacinths, tulips and daffodils are planted in fall, late summer blooming bulbs such as Dahlia, Canna and Gladiolus are planted in spring. Amend the soil with compost or manure to insure them a good start and plant in a well-drained area to prevent rotting. Generally, bulbs are planted at a depth of three times their diameter, and specific instructions are usually supplied on the packaging. Once planted, water your bulbs thoroughly and be sure they get watered regularly. Applying bone meal will give your bulbs energy during the growing season, but do not mix in too closely to the roots.
Will the unpredictable weather we have been having across most of the U.S. and other areas harm my garden? I have been getting asked this question quite a bit over the past couple of years. Generally, plants are pretty resilient. Buds that are forming on the trees early are sparked by the warmer temperatures in daytime but slowed down by the colder nighttime temperatures, which tends to balance out their progress. If there is severe cold for a prolonged period of time, buds could freeze and get damaged, but the tree produces enough buds to still have a bloom. More sensitive plants like old fashioned hydrangea ‘Nikko Blue’ that bloom on old wood are more susceptible to cold and time will tell. If there is die back on your plant, prune out the dead wood and apply a dose of a high phosphorus fertilizer. It could help to boost larger blooms from any undamaged buds. Hydrangea varieties that bloom on new wood, such as ‘Endless Summer’ and ‘Pee Gee’ should winter alright.
Some of my evergreens are a bronze color. Should I be concerned?Winter bronzing is normal on evergreens near the end of winter while temperatures are cold. Once the temperatures rise and new growth is stimulated, the foliage will turn back to a more vibrant green. Broken or dead branches are different in that they are completely dried out and brown. Those branches should be pruned off the tree in late winter/early springtime to prevent any further damage. Any falling or divided tree leads can be arbor tied to secure them and encourage upright growth. Split branches can also be arbor tied together, and if caught in time the cambium growing layer of the tree can mend. In the photograph above, the center upright Western Arborvitae are displaying bronzing and there are no signs of broken branches. As you can see the trees are healthy.
Have you heard about my new book,Landscape Design Combinations? My first bookA Guide to Northeastern Gardening covers recommended plants for zones 3-9 with topics including butterfly gardening, deer resistant plants, shade gardening, perennials, trees and shrubs, evergreens, general maintenance tips and more.
Landscape Design Combinations is a continuation of the previous publication, with greater emphasis on design, including numerous numbered and labeled photographs of successful landscape plans. Topics include elements of landscape design, designing for the seasons, how to build a natural stone patio or walkway, simple container combinations and garden styles throughout the centuries.
Both A Guide to Northeastern Gardening and Landscape Design Combinations were written to provide you with the tools needed to help you to create a successful garden. Click on the links below for more information and previews. I hope to inspire you!
The seasons have been shifting in the northeast, leaving many homeowners in much dismay when it comes to winter garden maintenance. Winter storms can hit late winter into early spring, causing more distress to plantings once they have experienced warmer than normal temperatures. As we await another winter storm, there are some precautions you can take to ensure the vitality of your landscape plants and protect them from possible damage.
SNOW WEIGHTED TREE BRANCHES: Most evergreen trees and shrubs can handlesnow build-up on their branches, but in the instance of a heavy snow, the branches may become weighted down. Certain Arborvitae are susceptible to the weight of snow pulling down on them and may have already experienced sagging branches. Further damage can easily be avoided by wrapping the branches together with arbor tie. The cloth tie cannot be seen from the outside, will prevent future damage from another snow, and the tree will look unscathed.
BROKEN OR DAMAGED TREE BRANCHES: Before an approaching storm, try to walk outside and inspect trees and shrubs on your property for any broken or damaged branches. If you do spot a damaged branch, tie the two split halves together by wrapping them tightly together with arbor tie. Start by wrapping the two halves tightly together and continue wrapping above and below the crack for extra support. If caught in time, the cambium (or growing layer) of the plant will repair itself and fuse the two parts of the damaged branch together. I have personally saved split branches on holly, azalea and arborvitae using this technique and the plants have recovered beautifully. Identifying these issues now and tending to them prior to the snow can mean the survival of your plant.
SNOW REMOVAL: While it is tempting to go outside and start removing snow from weighted branches it is also a good time to exercise caution. Under the snow-covered branches could also be a frozen layer of ice. Any manipulating of the frozen branches could result in easy breakage and permanent damage to your tree. A helpful tip is to very carefully dig snow from around trapped branches and allow them to spring back up on their own. Never shake branches with ice. It is best to let nature take its course and allow thawing to occur. The branches will gradually regain their shape as the ice melts preventing any harm to your landscaping.
SPRING BULBS AND SNOW: Just as your spring bulbs are emerging, a late winter snow storm in March can cause much distress and uncertainty. Besides having to tend with the snow, there is some reassuring news! While mulch protects dormant bulbs from cold, once they start blooming, a covering of snow will act as an insulator. The snow will help to hold in the natural warmth from the soil and provide protection. Once the snow is gone, you can continue to enjoy your bulbs!
As mentioned previously, plants are very resilient, and with a little care can bounce back and recover nicely after a major snow. With a March snow on the way, warmer days may not look promising at the moment, but Spring is right around the corner!
The temperatures are dropping rapidly here in the northeast and it is time to apply anti-desiccant spray to your broad-leaved evergreens to protect them from winter damage.
What is desiccation?: Certain broad-leaved evergreens are susceptible to winter burn and drying from harsh winter winds here on Long Island and anywhere where winter temperatures drop below freezing. Desiccation, or extreme drying is caused by moisture loss from the leaves by transpiration. A precautionary measure for this drying is the use of an anti-desiccant, which can help to prevent damage to your landscape plants. Anti-desiccant spray is an organic based spray application that lasts for approximately three months throughout the winter, and helps to prevent water loss from your evergreens.
Which plants should be sprayed with an anti-desiccant?: Apply an anti-desiccant spray to your broad-leaved evergreens such as holly, rhododendron, cherry laurel, skip laurel, mountain laurel, Japanese skimmia, leucothoe, aucuba and boxwood when the daytime temperatures start falling below 50 degrees (around Thanksgiving here in zone 7 Long Island). Apply when the temperatures are above freezing and there is no threat of rain or frost within 24 hours. (This tip applies to areas going into their winter season-temperatures dropping below freezing: 0 degrees Celsius or 32 degrees Fahrenheit.)
When to Apply: Apply anti-desiccant when the daytime temperatures start falling below 50 degrees (late fall/early winter). Apply when the temperatures are above freezing and there is no threat of rain or frost within 24 hours.
Dangers: Be sure to read all directions on the label since anti-desiccants can cause photo toxicity on some narrow needled evergreens such as Arborvitae and Spruce that could cause more harm than winter burn. Spraying in freezing temperatures will do harm to the plant. Do not spray in freezing temperatures and allow time to dry before temperatures drop below 32oF or 0oC.
How often should I apply anti-desiccant?: Sudden warm spells can trigger your evergreens to open their pores allowing for more water loss. If there is a winter thaw part way through the season it is recommended to re-spray your plants but only if the temperatures are to remain above freezing for at least 24 hours.
Where do I purchase anti-desiccant?: The most commonly used brands of anti-desiccant are Wilt-Pruf, Vapor Guard and Transfilm that can be found in nurseries and garden centers. There is a new brand of anti-desiccant on the market which requires only one application. Ask your landscape professional for more information.