Plants: What Can You Grow

• Long growing season and high humidity
  Long growing seasons with high humidity may favor plant diseases. We combat these by selecting resistant plants and encouraging good air circulation. Long growing seasons may allow insects to have multiple generations per year in the south compared to one or two generations per year farther north. Plant selection and planting times are important parts of management strategies.

• Summer nights are longer than those farther north.
  Nighttime in the summer represents time when plants are burning energy that they built up with photosynthesis during the day. In the north, shorter nights and cooler nights means plants’ rates of spending energy (respiration) slows; in the south, longer nights and warmer nights means plants expend more energy. Plants adapted to long days of photosynthesis and short, cool nights may not do well in an environment of shorter days and warm nights. Bottom line? Some northern or mountain plants like spruce or fir usually do not perform well in our area.
• It’s not how hot it gets; it’s how long it stays hot.
  We know it gets hot in the north and may get every bit as hot there as it does in the south. Differences occur in nighttime temperatures and the fact that it may get hot by late March or early April and continue to be hot for months. Plants may flower earlier, grow taller, and have weaker stems. They will probably need less fertilizer. Plants that may be grown in full sun in the north may benefit from some shade in the south (geraniums for instance). Likewise plants grown in some shade in Florida may thrive in more sun this far north.

• Winters are mild and may be wet.
  Without a protective snow cover, however, plants may suffer cold injury at temperatures much warmer than they could tolerate with a blanket of snow. Likewise, damp soil may be conducive to root-rotting fungi. Without good drainage, plants may rot in the ground.

• It’s not how cold it gets; it’s how it gets cold.
  Plants begin adapting themselves for winter in response to some environmental cue. It may be shortening days, cooler temperatures, or dryness. Plant responses to these cues include slower growth and in some cases leaf drop. Gardeners should not stimulate plants to continue growing into the fall (except for cool season plants). Avoid applying fertilizer or excess water. When plants are growing and fail to acclimate to the changing season, they may be seriously damaged by the first mild freeze. A plant that can tolerate single digit temperatures in February may be seriously damaged in October by temperatures in the upper 20s if it is not acclimated.

• It’s not how hot it gets; it’s how it gets hot.
  Spring may start with temperatures in the 70s or higher in January; but freezing temperatures may return as late as April or even May. Many plants break dormancy after an adequate amount of winter chilling. Once that threshold has been reached, a warming trend signals the plant to start growth. Many fruiting species such as cherries or plums will bloom in February well before the last hard freeze removes all the fruits that were set.

For more information, visit our Home Horticulture Website, or contact us by phone at 919.542.8202 or email Al Cooke.