Homegrown: Keeping your office plants healthy

This timely advice is from Iowa State University, Linn County Extension Master Gardener, Jane Schildroth:

   This is the time of year when office plants really struggle for a healthy existence.  Colleagues come to my door holding bedraggled green things in crusty pots, wondering what I might suggest to restore the life that might still remain in the containers.  Considering that many offices don't have windows, some have irregular heating and cooling and some have absent or absent-minded occupants, it is amazing that any office plants survive.  The lucky ones are those tended by the professionals who come in once a week and keep the public greenery attractive and healthy.

    Even when an office plant is carefully tended, it can still come under siege by various pests and diseases.  This can seriously harm the aesthetic quality of any indoor vegetation.  Mites, scale, mealy bugs, aphids and whiteflies are all pests that can attack.  If the leaves are yellowed, speckled, bronzed and covered in webs, it may indicate an infestation of mites. Hard or sticky brown bumps indicate scale and sticky, white powdery clumps indicate mealy bugs have moved in.

   Small flies surrounding your plant in a cloud may mean you have aphids or whiteflies.  Whiteflies can cause leaves to turn yellow and drop.  Aphids can cause stunted and deformed plant growth.  Both infestations produce “honeydew” which can feed gray or black fungi known as sooty mold.  Sounds horrible, doesn't it? 

  If these pests aren't enough, root rot is a fungal disease that is adapted to the soil.  With root rot you will observe browning and girdling of the stem and wilting and browning of the leaves.  Any infected tissue may become soft and mushy.  Another fungal disease to watch for is powdery mildew.  This can be rubbed off the plant surface, unlike leaf spot.

 All of these attacks can usually be controlled by following good plant care techniques.  Make sure to check any plants you move indoors after the summer is over and buy only vigorous and healthy-looking plants at the store.  Also pay attention to watering, since overwatering is one of the most common causes of plant problems.  Waterlogged soil does not have enough air for the roots to breathe so they become too week to fight off the fungi.  Be careful not to splash water on the foliage since bacteria and fungi can be spread this way.

 A plant with a disease problem should be isolated.  Sometimes you can simply remove the infected tissue or use a mild detergent solution on the pests before it comes out of isolation.  Other times, it is best to discard the plant and the soil and sterilize the pot with bleach before using it again.

 For suggestions of plants that thrive in various light levels, see https://store.extension.iastate.edu/ItemDetail.aspx?ProductID=5732

and match your choice of office plant with the lighting available in your space.  A hint from my office: check out the heat source and avoid placing your plant directly under or over it. Good luck as you create a pleasing environment in your work space with some attention to plant care in 2012!