Tag: Plant Healthcare

Winter Damage on Evergreen Trees and Shrubs

Winter damage on evergreen - looks red or burnt

Winter burn happens when plants dry out during the winter. Even during the colder months, evergreens continue to lose water vapor through their needles, which are modified leaves. The plant attempts to replace the water by pulling it from the roots. However, when the ground is frozen, the roots cannot absorb enough water to supply it to the dry needles. If the weather turns breezy, warm and sunny while the ground is still frozen (like today, in the Midwest), evaporation from the needles increases and water cannot be replaced fast enough. Discolored, brown or burnt-looking foliage may start to appear when this happens. In fact, winter burn indicators typically develop during warm weather in late winter and early spring.

Winter damage is often misdiagnosed as a disease or as damage from excessively cold temperatures. The damage which starts at the tips, is brown or rust-colored and generally on the side of the plant facing the sun and/or the side exposed to the wind, where the rate of evaporation from the needles or leaves is greatest.Dense yew evergreen with rusty looking winter damage

Winter burn can be more prevalent in years in which the ground freezes early before plants are acclimated to cold weather or when there is little snow. Without snow cover or mulch to insulate the soil, the ground can freeze more deeply. Although this is not always true, as the amount of snow did not matter this year because of the frigid temperatures, the ground is still frozen about 2 feet down.

Light pruning can remove the burn, however some lazy gardeners (ahem… the author) wait for the needles to completely dry and brush them loose / let them fall a bit later in the season.

Winter Burn Management Strategies

azalea evergreen leaves with rust colored winter damage on leaves

Water well in fall: One inch per week or saturate to the depth of 12” to 18” inches. Watering should be continued through late autumn into early winter as long as the ground is not frozen.

Mulch: Use mulch around the plant so the entire root zone is covered. This will reduce moisture loss.

Build a barrier to wind. A burlap barrier can deflect wind from the plant.

Promote good culture. Monitor the amount of moisture in the spring when the plant is coming out of a period of frozen ground, and low moisture availability. Water as needed if the rainfall is less than an inch per week.

Many broad-leave evergreens such as: holly, boxwood, yews and rhododendrons will also have some winter burn this year.

 

© The Naturarian

Houseplant Scale on Schefflera Arboricola

The Schefflera Arboricola is a fairly easy Midwestern houseplant to care for. When I lived in Florida, there was one growing in my front yard, right in front of the chimney. My Midwestern version is a smaller scale!

This time of year my butt has just about been kicked by Old Man Winter. I’m soooo over winter. My houseplants have had it also. Here I am, a horticulturist and should have noticed this earlier. I did see the shiny leaves, but I thought it was just where I had over-sprayed some horticultural oil. Nope, not that lucky. From a distance, these guys are hardly noticeable. However, just get a bit closer and you’ll see them all… Huddling on the midrib.scale insect on houseplant leaf

houseplant

Next I noticed my sock stick to the floor… The floor was sticky. Remember there are signs and symptoms to all plant problems. The shiny leaves and sticky floor are signs of a honeydew producing pest. Signs are observations that are directly related to the problem. A symptom would be the leaves showing some spotting.

Here’s the little guys close up, along with their honeydew which is just a sweet name for poop. In the wild, opposed to the tame of my living room, ants would be attracted to the sweet honeydew and protect the producer. Ants have been known to herd aphids (another honey-doer!) and protect them in little colonies. I’ve seen it, pretty weird!

scale insect on leaf

We’re not going to have freeloaders on my plants! I promptly dragged ‘Sheffy’ into the shower for a rinse. I would have preferred to use horticultural oil, but I was out. I did have an organic insecticidal soap.

houseplant getting rinced off in bathtub

Spray the plant down with water first, as the longer the soap spray stays liquid, the better job it will do smothering the pests.

Just for the record, using dish soap is not acceptable for a cheap substitute for horticultural soap. Now-a-days, the dish soap is not soap anymore, detergent is the main ingredient and modern soap lacks the fatty acids that are helpful in killing the insect.

Another few good tips to aid the recovery of your plant from scale:

  • Don’t over-water.
  • Don’t fertilize – forcing fresh growth is stressful on the plant and the pests like the new stuff better!
  • Place in sunny location.
  • Try to remove the honeydew, as sooty mold will grow on it.
  • Don’t be afraid to prune when needed – I cut many branches down to just lessen the surface area.
  • About once a week, spray off the plant and reapply the soap or oil.

© The Naturarian