Got Nature? Blog

Purdue Landscape Report: The hard freeze April 20th & 21st had many homeowners concerned about their perennial and annual plants in their landscape.  For the vast majority of perennial plants, there aren’t many issues long-term of concern.  Some foliage and flowers have significant damage, but the plants will recover, and possibly release new vegetative buds in severe cases.  The plants that suffered the most damage, and in some cases death, are the annuals planted by impatient landscapers and gardeners.  Planting annuals prior to the frost-free date (May 10^th in central Indiana) will more than likely cause a replant to occur.

Figure 1. Cold temperatures and cold on April 21-22 caused stress on many plants that have broken buds.

In addition to the potential stress from the temperatures, many trees received broken limbs due the combined weight of the leaves/flowers and snow load.

Figure 2. A Japanese Zelkova in full leaf with a heavy snow load.

If you maintain a client’s fruit trees (i.e. apples), there may be a significant impact on fruit production.  The Purdue Meigs Horticultural Research Farm, located about eight miles south of the West Lafayette campus, recorded a low temperature of 22^o F on April 21^st.  Dr. Peter Hirst, pomologist, indicated that at the current stage of flowering a temperature of 25^o F might result in a 90% bud kill.  Since there was a significant snowfall, the hope is that there was some moderation in temperatures.

Figure 3. Apple flowers on April 22 in West Lafayette. Photo by Tristand Tucker.

Figure 5. Apple flowers on April 22 in West Lafayette. Photo by Tristand Tucker.

Figure 4. Apple flowers on April 22 in West Lafayette. Photo by Tristand Tucker.