by Sheila Dunning | Aug 19, 2016
With all the media discussion of “bad” insects, like mosquitoes, many of the good guys are forgotten. One that has been very active this summer is the blue mud dauber, Chalybion californicum. These wasps are metallic blue, blue-green or blackish in color with very short narrow waists. During the summer, female blue mud daubers build nests by bringing water to abandoned mud nests made by other species of mud dauber wasps. They form new mud chambers, stock them with paralyzed spiders and a single egg, then seal the chambers with more mud. Their offspring stay in the chamber, feeding on the spiders, and then pupate in a thin silk cocoon. They spend the winter in the nest, emerging the following spring as adults.
Blue mud daubers are solitary wasps and not known to be aggressive. When the females have carried water to an old black and yellow mud dauber’s nest, she softens it and remolds it to her needs. The result is a very lumpy version of the originally smooth nest. Next she must fill the nest with food for her future offspring. The blue mud dauber prays on spiders.
If orb weavers, lynx or crab spiders are plentiful, the blue mud dauber is able to land on their web without getting entangled and pluck the web to simulate an insect in distress. When the spider rushes to capture its prey, the poor arachnid becomes the victim of the wasp’s paralyzing sting and is quickly flown to the mud nest. However, the preferred host of the blue mud dauber is the southern black widow. Even without the elaborate web game, this wasp can control a dangerous nuisance. Once at the nest with her spider victim, the blue mud dauber stores the paralyzed arachnid at the bottom of a mud cell and lays a single egg onto its body. When the wasp larva hatches it consumes the remaining body of the spider. With a full belly, the mature larva spins a papery silken cocoon within the mud nest and begins to pupate. The following spring an adult wasp chews a round hole in the end of the mud cell and exits it’s winter home.
As adults, the blue mud dauber feeds on nectar from flowers and honeydew secreted by insects. Should you encounter a large congregation of this normally solitary wasp, don’t be alarmed. It is probably just a bunch of male blue mud daubers gathering together to sleep it off, after a heavy day of “drinking.”
So, rather than having to cover yourself in DEET just to spend the evening on the patio, brave the heat (with water bottle in hand, of course) and spend the daytime hours watching the blue mud daubers prepare their nest for next year’s young. Maybe the media will pick up on wasp that are reducing black widow populations, rather than the dangers of mosquitoes.
by Sheila Dunning | Jun 22, 2016
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.
by Sheila Dunning | May 19, 2016
As cities expand, wooded lands and property with mature trees are being developed into commercial and residential sites. Unfortunately, the construction process can be deadly to nearby trees. In most cases, the trees don’t die immediately. Several years later as symptom development occurs in the declining trees, most people don’t associate it with the previous construction.
However, it is possible to preserve trees on building sites if the right measures are taken. Trees and their root systems must be protected from damage during the construction process. Roots absorb the water and nutrients that are essential to tree health. Damage to the roots can lead to the death of a tree. Compaction of the soil from equipment operation can hinder the tree’s absorption of nutrients.
The single most important action is to set up sturdy construction fences around the tree. The fence should be placed at least at the dripline of the tree’s canopy. As a general guideline, allow 1 foot from the trunk for each inch of the trunk diameter. Even with this method, 50% or more of the roots will be impacted by construction. No vehicles, building materials, waste, or soil should be allowed within the fenced area. No digging, trenching, or soil disturbance should be performed in that space. If construction equipment is allowed to operate close to the fencing, root pruning should be performed. A 4-5 inch deep trench should be dug on the outside of the tree protection zone with an air spade and then cut the roots cleanly with a saw. This root pruning technique will limit extensive damage to the roots.
The next step that will help the survival of a protected tree is irrigation during the construction phase. Stressed trees need plenty of water throughout the process. This means watering each tree about 2-3 times per week to a soil depth of 4-6 inches. Additionally, an application of 3 inches of organic mulch within the tree protection zone would help maintain soil moisture. But, do not place mulch against tree trunks because it could cause fungus growth to the trunk. If roots are not pruned at the edge of the protection zone, mulch should be placed over any roots that could possibly be driven over to reduce compaction.
Following construction the fencing can be removed, but irrigation needs to continue. However, the frequency should be reduced while the duration needs to be increased, to ensure that the tree receives enough water to maintain moisture in the top 12-18 inches of soil for the next year.
Simply keeping a tree on site does not mean it will survive the construction process. If measures to protect the tree cannot be taken, the most practical approach is to remove the tree prior to construction. But, for some of the historical mature trees it is probably worth the effort to preserve some horticultural heritage of the area.
by Sheila Dunning | Apr 21, 2016
Mountain laurel. Photo credit: Sheila Dunning, UF/IFAS Extension.
If you are lucky enough to live on the southern Alabama edge of northwest Florida, you may want to see if you can find mountain laurel blooming now near the wooded creeks. Its native range stretches from southern Maine south to northern Florida, just dipping into our area. The plant is naturally found on rocky slopes and mountainous forest areas. Both are nearly impossible to find in Florida. However, it thrives in acidic soil, preferring a soil pH of 4.5 to 5.5 and oak-healthy forests. That is something we do have. The challenge is to find a cool slope near spring-fed water.
Mountain laurel blooms. Photo credit: Sheila Dunning, UF/IFAS Extension.
Mountain laurel (Kalmia latifolia) was first recorded in America in 1624, but it was named after Pehr Kalm, who had collected and submitted samples to Linnaeus in the 18th century. The wood of mountain laurel was popular for small household items. It is heavy and strong with a close, straight grain. However, as it grow larger it becomes brittle. Native Americans used the leaves as an analgesic. But, all parts of the plant are toxic to horses, goats, cattle, deer, monkeys and humans. In fact, food products made from it, including honey, can produce neurotoxic and gastrointestinal symptoms in people consuming more than a modest amount. Luckily, the honey is usually so bitter that most will avoid eating it.
Mountain laurel in its native habitat. Photo credit: Sheila Dunning, UF/IFAS Extension.
One of the most unusual characteristics of mountain laurel is its unique method of dispersing pollen. As the flower grows, the filaments of its stamens are bent, creating tension. When an insect lands on the flower, the tension is released, catapulting the pollen forcefully onto the insect. Scientific experiments on the flower have demonstrated it ability to fling the pollen over 1/2 inch. I guess if you don’t taste that good, you have to find a way to force the bees to take pollen with them.
The mountain laurel in these pictures is from Poverty Creek, a small creek near our office in Crestview. This is their best bloom in 10 years. Maybe you can find some too.
Native range of mountain laurel.
by Sheila Dunning | Mar 22, 2016
According to the Atlas of Florida Vascular Plants, there are more than 4,200 plant species naturally occurring in the state. Nearly 3,000 are considered native. The Florida Native Plant Society (FNPS) defines native plants as “those species occurring within the state boundaries prior to European contact, according to the best available scientific and historical documentation.” In other words, the plants that grew in natural habitats that existed prior to development.
Native plants evolved in their own ecological niches. They are suited to the local climate and can survive without fertilization, irrigation or cold protection. Because a single native plant species usually does not dominate an area, there is biodiversity. Native plants and wildlife evolved together in communities, so they complement each other’s needs. Florida ranks 7th among all 50 states in biodiversity for number of species of vertebrates and plants. Deer browse on native vines like Crossvine (Bignonia capreolata), Trumpet Creeper (Campsis 
radicans), Yellow Jessamine (Gelsemium sempervirens) and Trumpet Honeysuckle (Lonicera sempervirens). The seeds and berries of Black-eyed Susan (Rudbeckia fulgida), Flowering Dogwood (Cornus florida) and Dahoon holly (Ilex cassine) provide vital food for songbirds, both local and migratory. Saw palmetto (Serenoa repens) provides cover for numerous birds and small mammals, as well as, reptiles.
Non-native plants become “naturalized” if they establish self-sustaining populations. Nearly one-third of the plants currently growing wild in Florida are not native. 
While these plant species from other parts of the world may provide some of the resources needed by native wildlife, it comes at a cost to the habitat. These exotic plants can become “invasive”, meaning they displace native plants and change the diverse population into a monoculture of one species. Chinese privet (Ligustrum sinense), Popcorn trees (Triadica sebifera) and Cogongrass (Imperata cylindrica) have 
changed the landscape of Florida over the past decade. While Water hyacinth (Eichhornia crassipes) and Hydrilla (Hydrilla verticillata) have change water flow in many rivers and lakes. These invasive species cost millions of taxpayer dollars to control.
By choosing to use native plants and removing non-native invasive plants, individuals can reduce the disruptions to natural areas, improve wildlife habitat and maintain Florida’s biodiversity.
If orb weavers, lynx or crab spiders are plentiful, the blue mud dauber is able to land on their web without getting entangled and pluck the web to simulate an insect in distress. When the spider rushes to capture its prey, the poor arachnid becomes the victim of the wasp’s paralyzing sting and is quickly flown to the mud nest. However, the preferred host of the blue mud dauber is the southern black widow. Even without the elaborate web game, this wasp can control a dangerous nuisance. Once at the nest with her spider victim, the blue mud dauber stores the paralyzed arachnid at the bottom of a mud cell and lays a single egg onto its body. When the wasp larva hatches it consumes the remaining body of the spider. With a full belly, the mature larva spins a papery silken cocoon within the mud nest and begins to pupate. The following spring an adult wasp chews a round hole in the end of the mud cell and exits it’s winter home.
