April 2005

Obsession Verbena By Catherine Evans

The Obsession verbena series offers a large number of color choices including Apricot, Blue with Eye, Bordeaux, Burgundy with Eye, Carmine with Eye, Coral with Eye, Lavender, Light Blue with Eye, Lilac, Pink, Purple, Red, Red with Eye, Scarlet, White, Eyed Mix, Pastel Mix, Spirit Mix and Formula Mix. Obsession combines outstanding pack and garden performance with high germination and usable seedling rate.

Germination percentage begins at 85 percent. This is actual germination, not a soft measure of potential, and seedling vigor enables you to transplant more plugs. Strong branching and short stems reduce or eliminate the need for growth regulators.

Obsession is earlier than most other seed verbenas on the market, with finish times of 12-14 weeks for 4-inch pots and 11-12 weeks for jumbo six packs (all depending on region).

With the help of culture sheets from S&G Flowers, I am able to bring you a quick guide to growing Obsession.

Germination

Prior to sowing, store Obsession seed in a commercial refrigerator (40¡ F) for five days. If it has been stored longer, that's fine. If you don't use all the seed at one sowing, re-close the bag as tightly as possible and re-store in the refrigerator in a container with a lid.

Sow seed in a sterile, soilless medium with an EC of 0.75, and maintain a pH of 5.5-5.8. The media doesn't have to be overly wet or dry prior to sowing. Temperature should be 75-78¡ F, and it is critical that it stay below 80¡ F, as germination will be reduced at this temperature and above. Provide nearly 100-percent humidity in the form of mist to the germinating seed for the first 48 hours after sowing.

Obsession seed doesn't necessarily need to be covered. However, you may want to provide some protection to the seed with covering. Use a coarse, #2 grade vermiculite and cover the flat lightly.

After the stem elongates and cotyledons expand remove plug flats from chamber and maintain temperatures of 75-78¡ F. After removal begin feeding with 50-75 ppm nitrogen from calcium and potassium nitrate. You may also apply a preventative fungicide at this stage.

Approximately 10-14 days later reduce temperature to 68-72¡ F. Allow medium to dry between waterings and increase nitrogen to 100-150 ppm.

Transplant

When plugs are at a transplantable size, the root ball should be big enough to pull easily from the plug flat. Using a sterile, soilless mix with a pH of 5.5-5.8 transplant plug into finishing container.

Growing on

Temperatures can be lowered to 63-65¡ F during the later stages of the culture. Allow root time to penetrate soil and expand toward the sides of the final container before doing this. Maintain plant turgidity and allow drying between watering. Fertilize with 150 ppm nitrogen and potassium nitrate, avoiding ammonium fertilizers. Obsession should not need any chemical growth regulators.

Common pests include Thielaviopsis, Pythium and powdery mildew, which are especially prevalent when both humidity and temperature are high. Keep conditions as cool and dry as possible, and use preventative fungicides. Aphids and thrips are common pests on verbena — as usual, to isolate infestations, apply appropriate insecticides after scouting.

Why Obsession?

Reduce costs — we hear this term often from growers all over the United States. I just have to look back at a few of our annual spring season review articles to see that reducing costs is on the top of the list for the following year. So, when the chance comes along to reduce costs while producing a quality product, you should welcome it. Obsession is one of those chances. As mentioned above, "Seedling vigor enables you to transplant more plugs. Strong branching and short stems reduce or eliminate the need for growth regulators." More useable plugs and less PGR costs sound like money makers/savers to me.

There are benefits in addition to the cost savings. Obsession produces bright flowers on lateral branches and contains a broad range of color. Oh, and it's quick to flower — 10-14 weeks, depending on container size and region. Quality and saving money is quite a combo.

– Carrie Burns