Category Archives: Common Questions

What to Do for Your Plants When Temperatures Plunge

For many, this winter has been characterized by abnormally mild temperatures punctuated by sudden and sometimes severe cold spells. These swings in temperature can be rough on plants. This is especially true when there is no snow cover. (Snow serves as a blanket to keep plants in the consistently cool and dark conditions that encourage and perpetuate dormancy.) Warm days when there is little to no snow may cause the ground to thaw. The sun’s rays and warming soil signal to plants that spring has arrived, even if the calendar says otherwise. Early flowering plants such as Hellebores, Snowdrops (Galanthus), Crocuses, Daffodils, and Tulips may begin poking up their heads and producing leaves and buds way ahead of schedule. What to do? Here at the farm, our garden staff tends to allow Nature to take its course, but here is some advice from our gardening experts:

  • Hellebores, which are generally the first perennials to flower as spring begins to stir, can handle some fluctuations in temperature, especially if you leave their winter-burned foliage in place to serve as a jacket. (Prune away the brown foliage after bunches of buds appear and spring temperatures begin to assert themselves.)


  • Daffodils are tough early bloomers. Foliage that emerges too soon may get frostbit at the tips but the plants will generally rally and produce their flowers on cue as spring arrives.


  • Several years ago, our Tulip trial garden endured a polar vortex plunge. The plants, many of them already in bud, wilted and sagged terribly in the cold and some stems and leaves developed a desperate watery look, but because the extreme cold was of relatively short duration (less than 24 hours), the plants made it through and were that much more beautiful when they blossomed.


  • For particularly exposed or vulnerable plants (or if you feel you must do something), consider covering them with a layer of Oak leaves and/or Pine boughs. Both serve to trap in some of the cold, which keeps plants dormant until spring. At that point, remove the leaves or boughs and enjoy your blossoms.


  • Some gardeners recommend mulching plants in advance of a temperature plunge to provide protection, but beware: Mulch is as good at trapping in heat as it is protecting from the cold. If you mulch after unseasonably warm days, your plants may continue to grow in what they perceive to be cozy conditions.


  • For larger specimens, such as early flowering shrubs and fruit trees whose buds have begun to swell, burlap or old bedsheets may be gently tossed over them to get them through a sudden cold snap, but beware of doing this in high winds, which could result in breakage.


  • Do not touch plants that have been subject to extreme cold. The frozen tissue of leaves and stems is especially vulnerable to damage. Keep your hands away and hope the plants recover naturally as temperatures rise.



Our Top 5 Garden Questions

Year after year, our customer service staff members spend as much time taking orders as they do answering questions and offering garden advice. They love to do this, especially because many are avid gardeners. Compiled below are the 5 most common questions they hear at this time of year. From advice on watering plants to pruning Hydrangeas, we hope you’ll find information you can use in your own garden.

The questions and answers here were supplied by Cathy Hughes, the Senior Horticulturist of the Customer Support Center and manager of the staff gardens at our facility in Torrington, CT.

Overwatering can be detrimental to plants. Water only when the soil is dry to a depth of 1″. Always check the soil before you turn on the tap.

Why aren’t the perennial plants I received this spring doing well despite being watered diligently (or religiously)?

Perennial plant material, which includes perennials, trees, shrubs and Roses, needs to be watered well after planting and then watered when the soil is dry to a depth of 1”. If rain is scarce, this generally means one deep watering per week, even in the hotter areas of the country. This is especially true of bareroot plant material. If plants are overwatered while establishing new roots, the quality of the roots will be compromised and the plants will not survive.

Why is the foliage of my perennials (or shrubs) wilting even though I’m watering diligently? Why don’t the plants recover after watering?

The foliage of plants often will wilt during the hottest part of the day as a response to the heat, but this does not mean the soil is dry, especially if conditions also have been humid. Always check the moisture level of the soil before watering. It should be dry to a depth of 1” before you water again. It’s important to remember that decorative mulch holds moisture in the soil. If the soil is staying too wet, it’s always best to temporarily remove the mulch from the base of the plants and gently cultivate the soil to aerate it. This should be done after every rain until the plant recovers.

The foliage of Phlox ‘Robert Poore’ is covered in powdery mildew. The plants need to be cut at the base and removed and discarded (not composted) or the mold will return in spring to re-infect the plants. Powdery mildew won’t inhibit the blossoms, but it’s not much to look at.

What’s the white coating on the leaves of my perennials (or vegetable plants)?

It’s the disease powdery mildew, and it can be controlled with neem oil, which is applied as a foliar spray. While the foliage looks unsightly, the overall vigor of the plant will not be affected. If possible, it’s also important there be good air circulation between plants and that all infected plant material be collected, bagged and discarded in the garbage in the fall. Do not compost this material.

What’s causing the holes in the leaves of my Roses?

If the damage results in a skeletonizing effect to the foliage (the leaf tissue between the large veins is eaten away), the damage could be caused by the larval stage of Rose sawfly (here in Zone 5 we begin scouting for this insect around Mother’s Day) or Rose chafers. Later in the season thrips may be the culprits. All of these insects can be controlled with a neem oil or Monterey Garden Insect Spray, or any insecticide recommended for Roses. While this damage is unsightly, it will only affect the overall health of the plant if the infestation is severe and is left untreated.

Hydrangea Endless Summer(R) blossoms on old and new wood. At the end of August, prune back some of the stems if the plant is growing too tall.  Remove some of the oldest stems at ground level to thin out the shrub as needed. In spring, prune out only dead wood once new growth emerges.

When do I prune my Hydrangeas?

The pruning of Hydrangeas depends upon whether they bloom on old wood, new wood, or both. Click here to visit our Grow Guide, which outlines how to prune different varieties.