May 26, 2010 Update
Wednesday, 26 May 2010 13:10
Viburnum leaf beetles are becoming active in nurseries and retail garden centers. See information and photos: Viburnum Leaf Beetle UMass and Cornell
High temperature is one of the most important factors to control in the retail yard. Shading and air movement are ways to help keep temperatures cooler for plants in the retail setting. The use of 50% shade of the midday sunlight will reduce light to appropriate levels. See the fact sheet Caring for plants in retail settings:
Two-spotted spider mites are showing up on Ipomoea. See message and photos on managing mites.
Spittlebugs: The white foam from spittlebugs can be seen now on many perennials as the spittlebugs move in from grassy areas. Most of the damage is cosmetic only and does not harm the plant. If the infestation is small, either handpick the spittle masses with a gloved hand or use a forceful jet of water to dislodge the nymphs. For more information and photo see this previous message.
Plant nutrition: Bedding plants in retail yards may be showing signs of lack of feed. With the recent prolonged high temperatures and frequent watering, fertilizer may have leached out. If new growth is yellowing and roots are healthy, fertilize with 200 ppm of a complete fertilizer such as 20-10-20 at every watering. Bedding plants usually recover easily because they are quickly purchased, and are planted out in the garden, fertilized and have room to grow.
Hanging baskets and patio pots are a different story. Plants in hanging baskets and planters will stay in those containers throughout the summer. The small volume of soil in a container is the only available source of nutrients for the plant compared to the much larger volume of soil available to the plants in a garden. Frequent watering causes much of the fertilizer to be leached out. If hanging baskets and planters are not fertilized in the retail sales area, or if controlled-release fertilizer was not used, all the fertilizer will leach out by the time the consumer buys the plants. The plants will quickly decline in quality once the customer takes the basket home. There are solutions. One is to fertilize baskets and planters in the retail sales area, on a weekly basis, using 400 ppm N, or using 200 ppm N at every watering. Another solution is to top-dress the basket or planter with a controlled- release fertilizer using 3-5 grams of N of a shorter term, 4-6 month material or use tablets according to directions. Retailers should communicate with their wholesale growers to make sure controlled-release fertilizer has not already been applied prior to shipping before fertilizing plants.
Tomato plants: Monitor for late blight and bacterial canker. See message.
Garden Mums should be planted as soon as possible upon arrival. See the message about early season care including fertilizing and crown buds.
Tina Smith, University of Massachusetts
Leanne Pundt, University of Connecticut
Paul Lopes, University of Massachusetts
