Distorted Leaves Caused by Mites

One of my favorite native plants is winged sumac.  I like this plant not only for its ornamental beauty, but also for its fruit that can be dried and used as seasoning and to make tea.  So you can understand my concern when one of my prized winged sumac plants had distorted leaves.

Eriophyid mite damage on winged sumac

Eriophyid mite damage on winged sumac. Photo Credit: Matt Lollar, University of Florida/IFAS Extension – Santa Rosa County

After doing a little research and speaking with one of our UF/IFAS Specialists, I was able to determine that the leaf distortion was caused by eriophyid mites.  Mites are not insects and are more closely related to spiders.  They normally have four pairs of legs, however eriophyid mites only have two pairs of legs.  They are microscopic, elongate, spindle-shaped, and translucent.

Eriophyid Mite

An eriophyid mite. Photo Credit: USDA, Agricultural Research Service.

Eriophyid mites cause galls (sometimes called witch’s broom) on various species of ornamental shrubs.  Symptoms include early and late bud distortion, distorted leaves, and possibly plant death.  In fact, the species Phyllocoptes fructiphilus is the vector for the viral disease of roses called Rose Rosette Disease.  Sometimes the damage can be confused with herbicide damage.

Control options are currently being evaluated for eriophyid mites in the home landscape.  Removing distorted plant material and removing it from the site can help prevent the spread of mites.  If you suspect eriophyid mites are the cause of your distorted plants then samples should be collected.  To collect samples: 1) Prune off symptomatic plant material and immediately place into a vial with rubbing alcohol; 2) label with collection date, plant species, and location; 3) mail to the Landscape Entomology Lab in Gainesville at P.O. Box 110620, Gainesville, FL 32611.

For more information on eriophyid mites and the sampling process, please see the fact sheet “Unusual Galls on Woody Ornamentals” from Erin Harlow and Dr. Adam Dale.

For more information on other mites that could be infesting your landscape, please go to this link from the Mid-Florida Research and Education Center in Apopka, FL.

Storm Damaged Landscapes

Storm Damaged Landscapes

Partly uprooted tree from hurricane. Photo credit: Larry Williams

Hurricane damaged plants should be cared for as soon as possible. Partially uprooted small trees and shrubs should be securely staked in their original positions. Until plants are reset, protect exposed roots and prevent drying. Soil, moist burlap sacks or moist sphagnum moss can be put on exposed roots. Remove damaged roots so the tree can be reset at ground level.

 

Once reset, trees should be secured. Two or three, four-foot long, 2 x 2 inch wood stakes can usually anchor trees with trunk diameters less than two inches. Stakes should be placed about a foot outside root ball and inserted eighteen inches into soil. Secure stakes to trunk with ties made from wide, smooth material or hose-covered wire. Trees two inches or larger in diameter should be guyed with three or four wires or cables. Guy wires are secured to deeply driven short stakes evenly spaced outside the root ball. Guy wires should be run through rubber hose and secured to trunk at only one level. Mark support wires with bright materials to prevent accidents.

 

Guy wires should be adjusted several times during growing season to minimize trunk injury. Support stakes and wires should stay in place for one year.

 

Soil should be filled around root area once the tree is staked into position. Firm around roots to eliminate air pockets and provide support. Excess soil over the normal root area can be damaging. Only replace soil that has been washed or worked away from roots.

 

In cases where all branches were destroyed, remove the tree. This is especially important for trees such as pine that do not normally regain their natural form. You may be able to keep other trees such as oaks, where strong bottom limbs still exist. However, emerging sprouts from ends of large, cut limbs will be poorly secured to the tree and are likely to fall from the tree during a storm. In addition, decay organisms usually enter these large wounds. Trees and shrubs that lost their leaves from high winds can usually be saved and should resume growth.

Any tree work, including tree removal should be done by a professional arborist, preferably a certified arborist. To find a certified arborist in your area contact the International Society of Arboriculture (ISA) at 217 355-9411 or at http://www.isa-arbor.com/. You also may contact the Florida Chapter of ISA at 941-342-0153 or at http://www.floridaisa.org/.

Reset plants should be watered twice a week and fertilizer should not be applied. Until re-established, fertilizer will be of no benefit and may injure new roots.

 

Plants exposed to saltwater, including lawns, should be irrigated with fresh water as soon as possible. Apply water more frequently than under normal conditions.

 

For additional information, visit http://sfyl.ifas.ufl.edu/disaster-prep-and-recovery or contact the UF/IFAS Extension Office in your county.

 

Camellia: Think Before You Limb Up

Camellia: Think Before You Limb Up

A few months ago I visited a property that had been renovated to clean up some limbs that were in danger of falling on the house.  Pruning tree limbs that are in danger of hitting a structure is always a good idea, but it’s important to look at the impacts this practice may have on the rest of a landscape.  Any time the light profile of a landscape is changed, current and future plant selection must be considered.  One often seen example occurs when trees grow to full size and shade out the lush lawn that’s underneath.  However, in this case, removal of limbs allowed more light to shine on some beautiful, old camellia bushes.

Camellia Planting and Care

Camellias do best in locations that receive filtered sunlight and are protected from the wind.  They like acidic, well-drained soils.  Trees and shrubs are generally planted 2″ to 3″ above the soil grade.  (2″ to 3″ of root ball should be exposed above the soil grade when the tree/shrub is planted.)  To help improve root oxygen exposure and help prevent a root rot situations, camellias can be planted slightly shallower than the previously stated recommendation.  For more plant establishment guidelines, please visit:  UF/IFAS Planting and Establishing Trees Guide

Scenario and Diagnosis

As mentioned above, the property in question was visited to diagnose sick camellia bushes.  Upon further inspection of the property, asking about recent changes to the landscape, and inspecting the bushes, it was clear that the camellias were receiving too much sunlight.  Sunlight damage was expressed by large brown sunscald spots on the yellowing leaves.

Sunscald on Camellia

Sunscald damage on camellia leaves. Photo Credit: Jed Dillard

The camellias had also been pruned incorrectly.  Camellias require minimal pruning.  They are normally pruned to control size or promote a tree form structure if desired.  Any pruning should be done before flower buds form in late summer.

Over Pruned Camellia

An incorrectly pruned camellia bush. Photo Credit: Jed Dillard

Solution

The best solution in this scenario was to dig up the affected camellias and move them to a location with more shade.  Sun loving shrubs were suggested as options to replace the camellia bushes.  It’s important to note that Camellia sasanqua cultivars are usually more tolerant of sunlight than Camellia japonica cultivars.  The recommendations were based on the Florida Friendly Landscaping principle of “Right Plant, Right Place”.

If you’re trying to find the right plants for you own yard, then you should check out the Florida Friendly Landscaping Interactive Plant Database.  The database gives you plant selection options for each area of your yard based on location in the state, plant type, and soil and light conditions.

What’s That Tree with the Purple Blooms?

What’s That Tree with the Purple Blooms?

Chaste tree.  The showy chaste tree makes an attractive specimen as the centerpiece of your landscape bed or in a large container on the deck. Easy-to-grow, drought resistant, and attractive to butterflies and bees, Vitex agnus-castus is a multi-stemmed small tree with fragrant, upwardly pointing lavender blooms and gray-green foliage. The chaste tree’s palmately divided leaves resemble those of the marijuana (Cannabis sativa) plant; its flowers can be mistaken for butterfly bush (Buddleia sp.); and the dry, darkened drupes can be used for seasoning, similar to black pepper, making it a conversation piece for those unfamiliar with the tree.

Vitex , with its sage-scented leaves that were once believed to have a sedative effect, has the common name “Chastetree” since Athenian women used the leaves in their beds to keep themselves chaste during the feasts of Ceres, a Roman festival held on April 12. In modern times, the tree is more often planted where beekeepers visit in order to promote excellent honey production or simply included in the landscape for the enjoyment of its showy, summer display of violet panicles.

Chaste tree is native to woodlands and dry areas of southern Europe and western Asia. It will thrive in almost any soil that has good drainage, prefers full sun or light shade, and can even tolerate moderate salt air. Vitex is a sprawling plant that grows 10-20 feet high and wide, that looks best unpruned. If pruning is desired to control the size, it should be done in the winter, since it is a deciduous tree and the blooms form on new wood. The chaste tree can take care of itself, but can be pushed to faster growth with light applications of fertilizer in spring and early summer and by mulching around the plant. There are no pests of major concern associated with this species, but, root rot can cause decline in soils that are kept too moist.

Dotted Horsemint Attracts More than Pollinators

Dotted Horsemint Attracts More than Pollinators

In 2016, I wrote an article for Gardening in the Panhandle called “Attract Pollinators with Dotted Horsemint” introducing readers to this tough native plant that supports native pollinators. If you have flowers in your garden, you probably have pollinators and a whole lot of other insects but if you want a plant that lets you observe a really diverse palate of bugs dotted horsemint Monarda punctata.

When I find I have some downtime at home I have a habit of wandering the yard looking for interesting insects. Admittedly, I usually have my phone in hand hoping to get a great photo or video of my arthropod visitors, but it is a productive task, too. As strange as it may sound, I can count this hobby as part of my integrated pest management landscape maintenance strategy – scouting!

My favorite plant to visit on my scouting run is normally not afflicted with pests, but it hosts so many different insects it always gets a stop on my rounds. When dotted horsemint is in full flower it is visited by a lot more than pollinators. I’ve recorded daily visits from assassin bugs, ants, beetles, flies, dragonflies, spiders, thread-waisted wasps, honey bees, butterflies, and moths.

Here’s a photo album of frequent visitors to my dotted horsemint from this summer – enjoy!

Leaf Spots Abound on Hydrangeas this Time of Year

Leaf Spots Abound on Hydrangeas this Time of Year

Hydrangea leaf spot disease
Photo credit: Larry Williams

It is not uncommon to see leaf spots on your hydrangeas during late summer and fall.

These spots are caused by a number of fungal diseases. Plant fungi and wet weather go hand-in-hand. Florida’s high humidity, heavy dews and frequent rains during spring and summer provide perfect conditions to allow fungal diseases to flourish. Bacterial leaf spots can be part of this foliage disease mix, too.

Common foliage diseases seen on hydrangeas this time of year include Phyllosticta leaf spot, Target leaf spot, Bacterial leaf spot, Botrytis and Cercospora leaf spot.

These foliage diseases are the norm rather than the exception as we move into the wet summer months and on into fall. As a matter of fact, you would be hard-pressed to find any hydrangea in our area without some evidence of infection now.

This late in the year it is more of a “grin and bear it” problem. In other words, it’s too late to do much about the fact that your hydrangea plant has leaves covered in ugly spots. By now many of the infected leaves are turning brown, withering and dropping prematurely from the plant.

Cercospora leaf spot is one of the most common foliage diseases of hydrangeas. Along with most of the leaf spot diseases, it begins as small dark-colored specks on the leaves. The small specks generally go unnoticed. But as the spots continue to slowly enlarge, mostly maintaining a circular shape, they become more obvious. With heavy infection, individual spots can coalesce forming larger irregular shaped brown areas on individual leaves. The individual spots may have a purplish halo with gray center.

There are some fungicides that can help prevent these leaf spots. But you’d have to begin treatment early in spring before any leaf spots exist and spray the plant every 10 to 14 days during favorable disease development (humid, rainy weather), which is pretty much our spring and summer months. These types of diseases are prevented, not cured. That’s the “grin and bear it” part of waiting until now.

The fungus survives on infected leaves. So, the best thing to do now is to remove and dispose of infected leaves. Also, be careful to not wet the leaves when irrigating the plants during the growing season.

New leaves of spring should be spot/disease free as they emerge. But the cycle of life for these leaf spot diseases will again result in spotted/diseased leaves on your hydrangeas next summer and fall without persistent treatment.

The good news is that these leaf spot diseases normally do not cause permanent/long-term damage for hydrangeas. They just make the plant look ugly.