In the Garden

Ralph Purkhiser, Purdue University Master Gardener

     The middle of October is the time to make some important decisions concerning the garden.  It is a time of transition, as temperatures drop and days grow shorter.  Decisions made now will affect the garden for next year and beyond.

     One decision is what plants to save.  Many of the plants that provided color to our summer gardens are actually tropical and sub-tropical perennial plants.  These plants may be used again next year if you are able to save them inside.  However, one must decide if it is worth the trouble.  My grandmother used to pot up her impatiens and keep them inside for the winter.  Since impatiens are shade tolerant, they do not need to be in a window; bright indirect light will suffice.  However, they are susceptible to mealybugs and sometimes that is more trouble than they are worth, especially when one considers that they are not expensive to buy in the spring as bedding plants.  Another option is to take cuttings and put them in rooting vials.  For some reason, the cuttings do not seem to get mealy bugs as much.  I have some cutting vials that have magnets on them, so they make nice decorations on the refrigerator or other metal surfaces.  As spring approaches, one may pot up the cuttings, which will have good root systems by then, and pinch them back to grow into bedding plants for next summer.  Other plants which may be treated in the same way include coleus, pentas and vincas.

     While there are many bulbs that bloom in the spring and are hardy in our climate, there are also many summer bulbs that are not exactly hardy.  Sometimes, one may be able to save some of these plants in micro-climes created by walls or large rocks, which are heated during sunny periods and give off heat to the surrounding area at other times.  You may know of people who have cannas, dahlias and gladioli that return in such areas.  A heavy layer of mulch applied after the frost kills the tops will increase the chances that such plants will return.

     Elephant ears and other taro-related plants are more tropical and less likely to make it through the winter.  However, one may dig them and save the bulbs in a cool, dark area.  Many sources recommend putting the bulbs in wood shavings, peat moss or shredded paper.  Do not store them in plastic containers, as they are prone to rotting when unable to breathe, but do put them in containers that keep them safe from rodents.  The same storage technique may be used for cannas, dahlias, gladioli, ornamental sweet potato and other tropical bulbs.  Any of these bulbs may be potted up in late winter to give them an early start on next summer, if you have a space to do so.  They will need bright light, as they will be spindly if grown in low-light conditions.

     Many other tropical plants used in summer landscapes may be kept through the winter as house plants.  I am afraid that I have far too many in this category, including tropical hibiscus, sienna, and many types of begonias.  I also have a huge assortment of houseplants that have spent the summer outdoors, especially many which have been clustered around some fountains.  These must be moved in before frosty mornings kill them.  Done properly, one should water them well and check for insects in the soil.  Do not be afraid to cut back plants to make it easier to keep them inside.  They may grow thicker stems and do even better next summer when returned outside.

      We have now passed the safe frost date of October 10, so I advise you to keep an eye on the weather forecast if you want to save plants for future use or to enjoy through the winter.  Even a light frost can be fatal for the most sensitive plants.