The environment impacts our plants in many ways. We are always happy to see the shift in weather to help the heating and air conditioning costs of our homes. Plants are also very happy when the weather changes to a more comfortable temperature. Extremes for moisture and temperature can be very damaging to our plants on both ends of the spectrum. This year we have seen a wide range of these problems which are negatively impacting our plants. To say we have a “normal” growing environment or weather pattern in Nebraska is almost unheard of and this year was unlike any we have seen recently.
Typically we are excited to see rain throughout the season. However, when the rain doesn’t seem to end, like this spring and even again now, this can harm our plants. There is such a thing as overwatering plants. Plant roots need to breathe too, if they don’t have the oxygen they need they can start to develop root or crown rot that can kill the plant.
Besides problems with root growth and development, many fungal diseases have been popping up on our trees this summer. There are many leaf spots on our trees such as maples, oaks, pears, and crabapples as well as on our vegetable crops such as tomatoes, cucumbers, and others. The cool, rainy environment this spring led to the infection which is showing up now. Spraying so late in the season won’t really help. The best thing for these plants is to just keep them healthy through the season and then use sanitation in the fall to reduce the diseases next year. Destroy fallen leaves at the end of the season by raking them up and throwing them into the garbage and remove annual plants from the garden. Don’t compost infected plant parts because the spores may not be killed in a compost pile. Leaves left at the base of the plant or vegetable plants left in the garden will make a good location for the disease spores to overwinter and move back into the plant next spring.
Hot temperatures can be problematic for our plants, especially when that heat comes on fast after such a long, cool spring and winter. We have had problems with leaf scorch showing up on plants when we had that swing of temperatures into the 100’s with high humidity. This extreme heat is damaging to our plants, but especially this year when they were accustomed to cooler temperatures with more than enough water available to them. Scorch is still apparent on trees even though temperatures have cooled back off. For the survival and health of our plants through extreme heat, keep a 2-3 inch layer of mulch around the plants and keep them well watered when rains end in the summer.
Excessive cold temperatures that we saw this winter can also harm our plants. The good thing for Southeast Nebraska was that we had snow cover most of the winter this year. If we had seen that much wind and cold temperatures without snow insulating the roots and crowns of our plants, we would have seen a lot more dieback.
Some of our plants did still have problems from the cold and some had problems from the high salt buildup around our plants from all the snow. Evergreen plants still transpire through the winter months. Desiccation happens when the moisture released from plants through transpiration exceeds moisture taken in through the roots. White pines see desiccation quite often in the winter months on the north side from the strong winter winds we see in Nebraska. This desiccation becomes even worse on plants that are in an area where snow with deicing salts are piled up each time we scoop snow.
There isn’t much to be done to fix trees now that desiccation has set in. For this coming winter, it would help to water the trees once a month on a warm day in the winter. You can also apply anti-desiccant products once every six weeks beginning after plants have completely hardened off, usually in late November. Continue applications through mid to late February. Avoid covering plants so heavily they become sticky with needles glued together. Have warm, soapy water nearby and clean out the sprayer immediately or equipment may be ruined by the product.