Early Detection & Treatment of Spruce Needle Cast Disease

Some familiar evergreens such as Colorado Blue Spruce may be susceptible to environmental stress. The recent pattern of summer drought, milder than usual winters and cool spring temperatures combined with wet conditions in the northeast have favored development of a fungal disease known as “needle cast”. Early detection and proper diagnosis is important in the treatment of this fungal disease and to ensure the health of your plant.

The best proactive means for preventing needle cast disease is to plant your Blue Spruce in the proper location and provide proper care. Blue Spruce prefer to be located in a well-drained soil in an area of full sun, meaning the plant should be receiving at least six hours of sunlight daily. A southern or western exposure suits this best. Prevent irrigation from directly spraying on the foliage of the plant. Constant moisture on foliage or over-watering can be a direct invitation for needle cast. Drip irrigation is recommended where possible, allowing the soil to dry between watering. Proper planting height is of course also necessary. Plant the tree at grade or slightly above the grade so that the root flare is visible. Do not plant too deeply. It is best that the lower branches have some air circulation above the ground.

The type of needle cast affecting Colorado Blue Spruce in the northeast is mainly Rhizosphaera needle cast (caused by the fungus Rhizosphaera kalkhoffii). While some browning and dropping of older needles in spruce is common, needle cast disease is noted by a distinct brownish-purple discoloration which appears on needles (usually towards the bottom of the tree) mostly in late summer, followed by the eventual death and dropping of older needles. In addition, the presence of black fruiting bodies on new growth in early spring is a sure sign. Typically, infections start near the bottom of the tree where foliage dries more slowly and progresses upwards. Lower branches may lose so many needles that growth at the tips stops, resulting in the death of the entire branch (photo below). Newer current growth may show no signs of the disease until during autumn and into spring.

Should your tree show signs of early needle cast, it is treatable. Needle cast can be effectively controlled with fungicides containing chlorothalonil. For moderate to severe Rhizosphaera needle cast, two properly-timed applications per year for at least two consecutive years (sometimes three) are required for control. After initial treatment, additional applications should occur when new needles are half elongated (around Memorial Day depending upon location) followed by a second application three to four weeks after the first. The timing of the two applications should be the same for the second and third year. Since needle cast is fungal and spread through spores, removal of branches showing early signs can prevent further infection, but the tree should still be treated with a fungicide and monitored on a regular basis.

The best method of preventing needle cast starts with proper planning, planting and monitoring. Early detection of any kind of disease leads to better results and remedies any further issues down the road. These tips also apply to dwarf forms of Blue Spruce, such as Picea pungens ‘Globosa’ (Globe Blue Spruce). Norway and Serbian Spruce are less likely to be damaged by needle cast and ‘Hoopsii’ and ‘Fat Albert’ cultivars of Colorado Blue Spruce are more resistant to the disease.

For more gardening tips Visit my Author Page

A Guide to Northeastern Gardening: Journeys of a Garden Designer Zones 3-9

Landscape Design Combinations

Dream, Garden, Grow! -Musings of a Lifetime Gardener

Gardening by Month: A Monthly Guide to Planning the Northeastern & Mid-Atlantic Garden.

February 19, 2020 0

Spring Maintenance of Birch, Boxwood and Hydrangea

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!

For more gardening tips and design inspiration along with personal musings…

Visit my Author Page/Purchase My Books:
A Guide to Northeastern Gardening: Journeys of a Garden Designer Landscape Design Combinations
Dream, Garden, Grow!-Musings of a Lifetime Gardener

June 4, 2019 0

Winter Damaged Hydrangea & Crape Myrtle-How to Treat

Winter Damage to Hydrangea & Crape Myrtle

This past winter has been recorded to be one of the worst for winter damage to foliage of plants in the past 25 years. I have witnessed winter damaged Hydrangea and Crape Myrtle on many properties I have visited and have been getting many inquiries as to how to remedy the damage that has occurred. Chances are that your plants will fully recover so I am passing on this useful information.

hydrangea winter die back — Hydrangea Winter Damage

If your hydrangea are sprouting new growth from the bottom only with no new sprouts on the upper stems and visible shoots on bare wood have a dark dried up appearance then they are not viable. To remedy cut back all dead wood down to where new growth is occurring. If your variety of hydrangea blooms on old wood you may not get blooms this year but your hydrangea should fully recover.

crape myrtle winter damage — Crape Myrtle Winter Damage

In the case of Crape Myrtles most of them survived but have dead top growth. It is advisable to wait until the end of June/beginning of July to cut back branches to new growth in order to allow the plant to sprout as much new foliage as possible. Other plants showing winter damage besides hydrangea and crape myrtle include butterfly bush and roses. Use the same practice to remove expired growth.

Due to the unusually harsh winter plant growth is delayed by approximately two to three weeks this season. New growth will have a slow start this spring but with some patience and proper care your plants should show full recovery.

As Always…Happy Gardening!

June 3, 2014 0

Pruning Perennial Salvia

Salvia ‘Maynight’ is one of my favorite blooms in the garden with its vibrant deep purple flower spikes starting at the end of May and lasting throughout the summer with proper pruning. When your plants are starting to look a little less desirable then is time to dead head. It is sometimes difficult to explain how to prune salvia so follow me on this. Take a look at any three fingers on your hand that are next to each other. When you prune your salvia you will be cutting out the center stalk that is done blooming. On each side of the center stalk you will see two other stalks with new buds and blooms forming. If there are blooms done on the two side stalks you can cut those out as well. Only cut the spent stalks and the new flowers will form.

I usually get about three blooms out of my salvia throughout the summer and into the early fall. By the second or third bloom you may want to give your plants a little plant food to give them a boost and add energy for the rest of the season. If your plants are brand new they may have been force bloomed so for the first season you may only get one or two blooms but come next year you will be able to push out three blooms if you time your pruning right.

With proper maintenance you will get full enjoyment from your Salvia with blooms throughout the entire summer and into fall!

May 26, 2013 2

May Garden Planting & Maintenance Tips

May is a great time for planting when the temperatures are in the 70’s. Here are some useful tips.

PLANTING DEPTH OF TREES : One of the leading causes of death for trees is incorrect planting. Large tree spades are often used to dig trees that cause the soil level to rise up covering the crown of the root ball. Plant your tree slightly above the soil surface so that you see a visible flare above the ground. When mulching make sure that the mulch does not come up above the root crown. Following these simple practices will help to ensure the health and life of your tree.

WATERING: Water throughly after planting and keep well watered throughout the first growing season. Be careful not to over water! Feel down by the roots to determine whether the plant is getting the correct moisture. Soil should appear moist but not wet or overly dry. Consider type of soil, time of year and amount of sun and rain. Watering every other day at approximately forty minutes per zone allows the water to penetrate deep enough to the roots. If you do not have a sprinkler system the use of soaker hoses is recommended. Water should be applied at a rate of 3/4 inch of water every three days or 1 1/2 inches a week. (One inch of water goes down 6 ” into the soil.)

PRUNING EVERGREENS: Most evergreens can be pruned at any time of year except when the weather is too hot or right before temperatures start to drop below freezing. Ideally, late winter and early spring are best. Most evergreens will not take well to hard pruning. The only exception is Taxus (Yew) which may rejuvenate over time. No plant is completely maintenance free so keep your evergreens trimmed to their desired size. This will also keep them full and healthy and prevent thinning out. NOTE: Evergreens will shed their needles or foliage in the Fall/Spring to allow for new growth. If any branches appear brown or dead after planting or after winter, trim them off and allow the plant to rejuvenate. When in doubt ask a professional.

PRUNING FLOWERING SHRUBS: Prune flowering shrubs and flowering evergreens after the bloom. Flowering shrubs such as hydrangea bloom on the last years growth and will not bloom if cut back in Spring with the exception of the Endless Summer Collection which blooms on new wood (click on hyperlink for article on pruning all types of hydrangea). Prune Lilac for shape after flowering in spring.

FERTILIZING: Feed plants in spring. For new plantings allow the plantings to become established then apply a slow release organic fertilizer or apply a “starter” formula when planting. For established plants there are several products on the market. Be careful not to buy a concentrated product that will burn the roots. A slow release or organic fertilizer such as Holly Tone is recommended. Also when planting, a mixture of hydro-gel along with a slow release fertilizer will help to retain moisture in your plants.

INSECT CONTROL: Periodically check your plants for insect or fungal damage and treat if needed. It is advised to use a regular insect control maintenance program to keep your plantings healthy.

LAWN CARE: Ideally sod lawns are best planted in spring and seed best planted in the fall. Your lawn should also have a regular maintenance program to keep it at its best-ask your professional.