As I type this article, the outside thermometer is showing 10 degrees F. Ouch! And the calendar reads March 4. Double ouch! Winter is stubbornly hanging around for a few more days, maybe weeks. Eventually, the dreary cold weather will surrender to spring and life will return to the woods. However, subtle changes are occurring now if one looks closely. Through a process called plant thermogenesis, heat is generated in the spadix of skunk cabbage. This allows the spadix, a flowering structure, to emerge from the cold ground, even through a blanket of snow, to claim the title as the first native plant to flower in the woods. Days later as the ground soaks up the sun’s warmth a plethora of spring ephemerals will blossom and convert a brown landscape into a colorful bouquet of floral delight. This is the time of year I most enjoy taking a walk through[Read More…]
Archives for March 2019
Woody plants in cities and home landscapes are threatened by scale insects. Learn how to choose the best control for your scale problem.
Volutella stem and leaf blight caused by the fungal pathogen Volutella pachysandricola can cause major damage to Pachysandra, destroying large areas in a bed. (Fig 1) Infected leaves first develop tan or brown blotches with dark brown margins, which expand, often with concentric lighter and darker target-like zones. (Figs 2a,b) Stem and stolon cankers appear as water-soaked diseased areas, turn brown, shrivel and often girdle the stem. causing stem dieback. (Figs 3a,b) Orangish spore masses develop in the cankered areas and the underside of infected leaves. (Fig 4) Volutella blight of pachysandra is often associated with plant stresses such as recent transplanting, exposure to bright sunlight, scale insects, and winter damage. Normally this disease does little damage to vigorous plants, thus providing good growing conditions is the most important control measure. Unfortunately, a dense planting bed of pachysandra is the desired horticultural outcome, thus thinning the planting to allow better[Read More…]
It is easy to confuse Hemlock (Tsuga spp.) and Yew (Taxus spp.) unless you can see the overall plant habit or have them both side by side. Further confusing them is that both species may be pruned into hedges or other shapes that obscure the natural plant habits. Hemlock has short needles, 1/4 – 3/4″ long, green above and distinctly whitish silver below due to prominent white stomatal bands. Cones are 1/2 – 1″ long, ovoid, and pendulous. Yew has a slightly longer and wider needle -about 1/2 – 1 1/4″ long, dark green above and light green below, overall coarser texture compared to hemlock. Cones resemble berries, the brown seeds are covered by a fleshy red aril (seedcoat).
Fungal diseases of ornamentals will always be a limitation to profitable plant production and management—how significant that limitation is in your hands. Fungicides are effective in reducing the risk of loss– in numbers, in quality and in terms of aesthetics. However, fungicide costs in terms of product cost, number of applications and labor need to be evaluated against the benefits their use provides. It is important to keep in mind that these costs and benefits vary between greenhouse, nursery and landscape use; in the case of greenhouse and nursery, these costs are also weighed against plant (commodity) prices. That said, there are several effective, and cost-effective fungicides available for each type of user, keeping in mind that what is effective and cost-effective for one may not be effective for another. For example, a pathogen like Rhizoctonia infects plants in the greenhouse, nursery, turf, and landscape! What is best for one[Read More…]