Yellowing leaves after heavy rains: chlorosis
With the abundance of rain and unusually mild temperatures in spring 2019, we’ve seen plants growing by leaps and bounds in very short time spans. And as all that rainfall percolates through the soil, soluble minerals move with it, washing essential plant nutrients below the root zone, putting them out of reach at a time when plants need more of them than usual.
While native plants are more accustomed to our natural weather patterns, and more accustomed to the natural level of nutrients in our soil to begin with, adapted ornamentals may struggle a bit with these swings and need a supplemental boost in spring.
But before you apply any product, even an organic one, you need to know just exactly which nutrients your plant needs. Most nutrient deficiencies manifest as some sort of yellowing, which we refer to as chlorosis. And while there are over 20 essential plant nutrients, plants require most of them in such minute amounts that only a handful will ever be so low in the soil as to cause any issues. Also, plants can move some of these nutrients around within their own bodies, buying time for the external environment to improve.
There are two deficiencies that affect us most.
NITROGEN deficiency manifests in OLDER leaves that turn yellow, while new leaves appear healthy.
IRON deficiency manifests in NEW leaves. Common in alkaline soils, it’s easy to spot because veins are green and leaves are pale green or even yellowed. Plants aren’t able to move iron around once they’ve incorporated it into their tissues.
Nitrogen is the nutrient needed by plants in the highest quantities, so it’s the most common nutrient in fertilizers. That’s the first number in the ratio—like 8-2-4.
Iron deficiency is very common for gardeners in the western U.S., where soil pH tends towards the alkaline side, and it manifests as interveinal chlorosis: yellowing of the leaves between the green veins, on new leaves.
URBAN MYTH: No matter what you read or hear, putting nails in the ground around your plants DOES NOT add iron!
Early spring wildflower seeds, including bluebonnets, should be getting dry and brown enough to clip if you want to save some seeds. Remove the seeds from the pods and let them dry completely in the house before storing. Plant in October and November.
KLRU’s Vice President of Education Benjamin Kramer and his family planted bluebonnets last fall in their yard. As a nod to CTG producer Linda Lehmusvirta, they named them the Linda bluebonnets. What a fun family project and she is certainly proud to have a bluebonnet named for her.
From Carollton, Monica and Darrell Miller are celebrating their first hydrangea bloom. They’re growing this beauty in a container on their part shade patio where it’s obviously thriving!