Crop Culture Report: Hypericum Ignite Series

April 9, 2009 - 11:41

Hypericum has a long history dating back to ancient Greek times. It was believed to possess magical properties that dispelled evil spirits. There was a common medical belief that sleeping with a piece of hypericum under your pillow on St. John’s Eve would protect one’s health during the following year. Today, most people are familiar with hypericum as cut flowers with nice berries on dark-green leaves.

Ball has developed a growing program to make this normally July-flowering perennial shrub actually flower in late August with a crop time similar to an annual. Because of the Ball-recommended advanced growing technique, hypericum Ignite is perfect for early fall in a very wide range of climates in North America. This tough plant can take the heat and humidity of summer, and will initiate flower on daylength regardless of high or low night temperatures.

Variety Information

Because of its unique, compact habit, the new hypericum Ignite series has the capacity to be used as a container plant from 41/2-inch pots to 2-gallon containers. All three varieties — ‘Ignite Red’, ‘Ignite Scarlet Red’ and ‘Ignite Scarlet’ — are well branched with short nodes in order to fit container production.

Home gardeners can use it in a single container on their porch or patio, or place it in mixed containers where the red berries will give a new look to their fall garden. The great color contrast of the dark-green leaves, yellow flowers and red berries is ideal for early fall sales. With lower temperatures, the berries can last until the end of October or until the first strong frost. When planted in ground, home gardeners will be rewarded with a 4- to 5-foot tall shrub flowering in July.

Seasonal Care and Hardiness

The Ignite varieties have shown a great tolerance for hypericum rust, a major issue for other hypericum, and are cold hardy to Zone 4.

After the first deep frost, hypericum will lose its leaves and enter dormancy. Containers can also be overwintered after plants go into dormancy. Only dried up branches have to be cut back to the ground, and the plant can be stored in a dark cool garage or shed. When the plants come out of winter dormancy, they should be grown in full sun with plenty of water to get a good start in the container, or they can be transplanted into the landscape.

After transplanting in May and using the following guidelines, expect flowering from the end of August to the beginning of September. The crop starts with a specially prepared liner to be transplanted between weeks 18 and 22 depending on the container and projected plant size:

  • one plant per 41/2-inch pot to 1-gallon container
  • three plants per 2-gallon container and larger

Transplant and Pinch

Young plants should be transplanted immediately upon arrival. Wilted plants will not recover and will branch unevenly. Do not allow media pH to drop below 6.0, and maintain a 2.5 EC level. A pH lower than 5.8 may cause iron toxicity.

For best results, grow outside in the full sun with drip irrigation. If grown in a very well-ventilated tunnel or greenhouse, the PGR applications have to be adjusted accordingly. Heat and high humidity are not a problem, but plants need to acclimate when first moved outside to avoid sunburn of the leaves.

It is advantageous to initially grow the plants with higher ammonium to promote maximum branching which will result in a fuller, more uniform crop. Use 20-10-20 fertilizer for the first six weeks of the crop and then change to 15-3-20 fertilizer. It is necessary to pinch or even machine shear this crop up to two times, back to one full leaf pair. The last pinch date is July 1.

Hypericum is a long-day plant with a critical daylength of 131/2 hours. After the last pinch, the height of the plant can be controlled with 45- to 75-ppm Topflor (flurprimidol) with one to three applications depending on growing conditions. It takes about eight weeks from the last pinch date to flower and about two more weeks to show the first berries in September.

Finishing

Hypericum Ignite ships very well as finished plants if packed with dry foliage. If plants are stored with dry foliage in a cooler between 48 and 52° F for a couple of days they will lose open flowers, but the berries and foliage will not be damaged. Leaf shine can even enhance the look and color contrast on the hypericum, making this variety a premium eye-catching top seller for fall.

About The Author

Michael Henzler is product development director of vegetative products for Ball Horticultural Co. He can be reached at mhenzler@ballhort.com.

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