GARDENING : Diagnosis, First Aid for Plants
Asking yourself questions often provides the clue as to why a plant is ailing. It often points to the solution, too.
But do this methodically, never assuming anything and checking everything. Keep careful notes. If you’re stumped, the notes could help someone else pinpoint possible causes even without seeing the plant.
Start with: Is this normal for this time of year? For example, most gardeners understand that leaf drop in the fall is common with deciduous plants. However, many evergreens also routinely replace some leaves at certain seasons.
Is the entire plant affected or just one side? Did one side show symptoms first? If so, when? Was the decline sudden or over a period of time? How does adjacent vegetation look? Are more insects than normal present, indicating a plant under stress? Is just one plant in trouble, or do similar ones show the same symptoms? Bark splitting? Leaves yellowing?
How long have you had the plant? Even with the best care and most favorable growing conditions, some are unlikely to survive more than a year or two.
Answers to such questions may be all you need.
If not, consider what’s adjacent to the plant: an alley, a swimming pool, a driveway, a patio, the neighbor’s yard? Has something happened with them recently? Could new paving or a patio expansion have damaged extended roots or changed drainage? Did the pool overflow? Some chemicals spill?
Was a soil sterilant or vegetation-killing chemical used under or around the plant within three or four years? Some persist in the soil for years but are not picked up by a plant until roots grow into the area. Did the neighbor apply some in his yard, even if you didn’t? Another possibility: excess fertilization.
A persistent, premature leaf drop calls for a check of watering practices. A sprinkler system may produce a fine lawn, but it seldom supplies sufficient deep moisture for trees and many shrubs. Remember, too, that excess water kills a plant as easily as extreme dryness. Wilting foliage can be an early symptom of either.
Probing a few inches into the soil with a trowel, augur or long-blade screwdriver usually supplies the answer. Make it a practice to water in the morning so foliage dries before dark. In general, too moist conditions favor plant diseases.
Was it planted too deeply or shallow? Is there excess mulch?
Are underground animals a possibility? A neighbor’s prized collection of agaves was ruined by gophers who ate the succulent stems before their tunnels were noticed.
A general yellowing of many leaves can be caused by lack of fertilizer, extreme sunlight or high temperatures. If only older leaves are affected, it could be lack of nitrogen or potassium, soil high in salts or poor soil aeration. Yellowing of youngest leaves suggests lack of iron or chemical damage. Marginal burning usually is traced to salinity.
If some leaves look terrible but most leaves look OK, the plant probably is healthy.
If the plant dies, be sure to examine the roots and the soil surrounding them. A bad odor often means the soil was kept too wet. Limited root development may indicate the same, or lack of water.
