Water, Water Everywhere is Never a Good Thing. Identifying some of this year’s plant problems.

2018 was the wettest year on record here in Central Ohio and so far, 2019 is outpacing last year. It has been the number one topic of conversation and a point of concern for everyone in this area. From the farmers running out of time to get crops planted, to homeowners just trying to get their lawns mowed without getting stuck in the marshy areas, even our own landscape company struggles to keep on schedule due to all the rain delays. While trying do the least amount of damage possible to each client’s property we are trying to beautify, we have had to be inventive, sometimes simply by putting down sheets of plywood to get us through the wet areas in the client’s yards. So far, the weather has not won the battle and I will take excess rain over drought any day.

Unfortunately, all the excess rain has caused many plant issues as well, resulting in an abnormally high number of emails and calls from clients with concerns about the condition of some of the plants in their own landscape. Fluctuation between warm and cold during the winter caused more severe die back than normal, the wet weather brought on stem blight, fungus, leaf spot and other diseases, perennials in low areas simply drown and the prolonged cool temps caused slower than normal leafing out of plants and trees. Luckily as the days are getting warmer, the warmth seems to be bringing the plants out of their not so normal lethargic growth rate, catching up to where they should have been a month ago.

Amazingly, several plants thrived with the wet weather. Water thirsty perennials, like Iris and Daylilies, loved the spring by showing greater than normal growth and flowering trees, such as Crabapples, were absolutely stunning when in full bloom, as were the Lilacs. Hopefully the Hydrangeas follow suit!

So, to help address some of the concerns, below are plant issues we have observed so far and their recommended treatments.

Winter Dieback:

· Shrub Roses took a big hit, dying back almost to the ground, but have recovered nicely when given a good spring fertilization with a 12-12-12 or similar fertilizer. Prune out any dead branches if not already done.

· Hydrangea died back as normal during our cold winters and now have leafed out as they always do, liking the abundant rainfall. Prune back dead branches if not already done.

· Our older Bamboo canes died, but nothing completely stops it and the new shoots came up as normal.

· Rose of Sharon took quite a hit, dying back to approximately 12-24” off the ground.

Fungus:

Leaf spot on Serviceberry

Serviceberries that are in shade have interior leaves that are already in fall color and are falling off. Upon inspection there are reddish brown spots with a yellow halo on the leaves which is Entomosporium leaf spot caused by the humid, wet conditions. To treat, rake up and dispose of the fallen leaves and spray tree with a copper based fungicide such as Bonide Copper Fungicide which is available at Lowe's or check with your local nursery.

Powdery Mildew on Ninebark

Grayish-white leaves on Ninebark is Powdery Mildew, or Podosphaera aphanis var. physocarpi, again caused by humid weather and poor air circulation. Powdery Mildew is spread by the wind and germinates when it lands on a dry leaf, so if you have powdery mildew, run water over the leaves during the time of day the leaves will dry quickly in order to knock the spores of the leaves. Other treatments are a Fungicide such as Funginex or Neem Oil sprayed on the plants. Powdery Mildew is non host specific, so other plants are suseptable as well. Treatment is necessary to keep it from spreading.

Azalea Leaf Gall

For the first time this year strange pale green and powdery white growths appeared on the new leaves of our Herbert Azaleas. These are Azalea Leaf Galls caused by Exobasidium vaccinia fungus brought on by the cool, wet and humid weather. The fungus invades the new leaves causing the leaf to swell and form galls. Pick the galls off and dispose of them before the white spores form and can be spread by the wind, are spread by splashing rain and can overwinter on the plant, affecting new leaves emerging in the spring. Fungicides are generally not needed as the galls are unsightly but not detrimental to the plant.

Blackspot on Rose

Roses should be treated now to protect them from Blackspot, Aphids, Japanese Beetles and other chewing insects. Blackspot is identified as a black spot on the leaf, causing the leaves to turn yellow and fall off, starting with the lower leaves first and defoliating the plant quickly, weakening it. Remove fallen leaves so the spores can’t splash back up on the wet leaves where they germinate. Aphids, Japanese Beetles and other insects will chew on Roses and can be contolled with a systemic insecticide such as Orthene. Fungicides, such as Funginex, can be mixed with Orthene to control both disease and insect control simultaneously.

When using any chemicals, please use protective wear and follow all instructions on the container.

One thing of note. Even though we may be happy to see some drier weather, please remember to water your newly planted or young plants and young trees during dry periods this summer and early fall. The plants put on excess growth due to the availability of all the water this spring and will need supplemental watering to prevent stress to the plant and leaf drop when it gets hot and dry.