12.8.10

Annual Plants In the Fall Garden

Geranium hybrid
New Guinea Impatiens
It's that time of year when we start to think about planting the Fall crop of annual plants such as New Guinea Impatiens, wax begonias, Impatiens, Coleus, and so on. Despite the torrid heat at the moment, we're 7 months into the year, and the days are getting shorter. Soon ( maybe) the temperatures will lower, enough to allow planting annuals. Masses of colorful flowering plants in full view are a great way to cheer up a landscape. The local retailers will start stocking these plants in another month or so, but I caution the careful reader about buying plants too early in the year. My experience has shown that planting too soon ( before October) leads to a lot of heat stress on the plants. This heat stress often hastens the deaths of the plants.

September is a good month to prepare planting beds by digging up weeds, mixing slow-release fertilizer into the planting areas( Osmocote, Dynamite, organic rose fertilizer) and by allowing the beds to "fallow" i.e. rest and recuperate from the previous crop. Try to dig down and turn the soil at least 6 inches deep where possible, and adding sandy compost helps aerate the soil. Then you can consider adding the plants when the time comes. One of the biggest mistakes I see is the wrong plant in the wrong place. Most annual plants are fairly thirsty, yet I see people plant their Impatiens at the base of Canary Date Palms. The palm needs great drainage and to be rather dry, the Impatiens need water almost every day. To add insult to injury, people then mound mulch around the Impatiens and up against the palm trunk, a tactic called "volcano mulching". This can kill a Date Palm rather fast. If you want the flower / palm effect, plant the Impatiens around a Veitchia Palm or Royal Palm which likes the extra water.
Salvia leucantha hybrid

Annuals are high performance, high demand plants, and should be planted and cared for as such. You should try to grow these plants in slightly raised beds, and to be prepared for rapid weed growth. A  layer of mulch should be applied after planting to control weeds, but be aware that it won't prevent their growth 100%. Plant fast-growing annuals on 12 inch centers or further apart. The plants will grow to 14 to 18 inches in diameter each and the extra spacing will allow more sun and air to the centers of the plants. It's OK to tip-prune annuals, since most will branch at the cut area and make bushier, more floriferous plants. Use a sharp clipper and prune gently. I've seen some people use a machete to prune their Impatiens, and I'll never forget the unfortunate results.....

The last step in preparing for annuals planting is to choose an area with at least 4 hours of sun per day, preferably morning sunlight. The late afternoon sun is extremely hot and can shorten plants' lives considerably. If you mix annuals, try to plant the same type of plants in large groups. The group planting effect is more vibrant than the one-plant-here / one-plant-there style.

Wax Begonia
      Annual plants can be a fantastic addition to your garden, but be informed of the needs of the plants before you buy them. Annual plants are not set-and-forget plants, they are plant-and-tend plants. As with so many garden projects, you get out of them what you put into them. Experiment with a few types in hanging baskets or in containers for a new twist on gardening efficiency.

Craig Morell
Pinecrest Gardens

1 comment:

  1. the best annual (which actually has long-life of 2-3 years in south florida) is Cora Vinca Periwinkle (Catharanthus roseus 'Cora')....because it can handle wetness of south florida summers without dying like other periwinkles! I've had great luck with mine. Very compact and beautiful! copy/paste link:
    http://www.finegardening.com/plantguide/catharanthus-roseus-cora-series-periwinkle.aspx

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