11/26/2014
Unraveling the Confusion: Growing Blooming-Sized Digiplexis
Jeremy Windemuller
The exotic-looking intergeneric foxglove hybrid Digiplexis was invented by crossing a hardy
Digitalis purpurea with a tropical orange-flowered digitalis relative native to the Canary Islands called
Isoplexis canariensis. Since it’s a Zone 8 perennial that does require some vernalization to bloom, a bit of knowledge is necessary to produce a beautiful flowering crop of Digiplexis. Here are some guidelines.
Potting and timing
Start by receiving vernalized 72-ct plugs in spring (January through April). It’s very important that the plugs you start with have been properly vernalized or your crop will have no flowers. Plant one plug directly into an 8-in. or 2-gal. container, using a well-drained growing media with a pH of 5.5 to 6.0. They should finish in 8 to 10 weeks at 55 to 60F (12 to 15C). Alternatively, you could grow Digiplexis in 12-in. decorative color pots. Just add a couple of weeks to the finish time. These plants develop a large, bulky crown, so it’s best not to pot them up into smaller containers.
Cultural recommendations
Fertility | Digiplexis are moderate feeders. Feed them 100 to 125 ppm Nitrogen in a constant liquid feed during the rooting stage and then increase the rate to 200 to 250 ppm Nitrogen in a constant liquid feed when forcing them into bloom. The suggested EC rate is 2.0 to 3.0 using the pour-through method.
Moisture | Digiplexis grows best with moderate-to-consistent moisture levels. Because of its dense rosettes of large leaves, it can be difficult to get the water down to the roots, so it’s best to use drip irrigation on this crop if possible. If conditions are too dry, mites can become a problem. Be sure to irrigate in the morning to allow the rugose foliage to dry by evening.
Lighting | Growing Digiplexis under high light conditions and cool temperatures will keep them more neatly compact, making them easier to ship and merchandise. Growing under clear plastic or outdoors in frost-free climates is recommended for best light quality.
Temperature
Growing temperature | In frost-free climates, Digiplexis can be grown outdoors in early spring at 45 to 60F (7 to 15C). If growing indoors, greenhouse temperatures should be maintained at 50 to 60F (10 to 15C). This is a tender plant—do not let temperatures fall below 38F (3C) during production! You can expect flower initiation to occur within 6 to 8 weeks after plants are rooted out.
Pests and diseases
Proper watering techniques will help to avoid potential disease issues. Pests such as aphids and spider mites can occasionally affect a crop of Digiplexis. Scout regularly for these pests and treat as needed.
Finishing tips
Spacing | Digiplexis is a large plant that requires ample space to grow. Its foliage will extend beyond the edge of the container. Be sure to space plants well in production to achieve well-rounded specimens with the maximum number of secondary flowering shoots.
Pinching | It’s a good idea to pinch out the initial main flower stem to stimulate production of many additional secondary flowers and to bulk up the plants. If left unpinched, the main flower stem will grow very tall and will twist and curl with age.
PGRs | If grown under cool temperatures and high light levels with proper spacing, PGRs shouldn’t be necessary.
GT
Jeremy Windemuller is a grower and trial manager for Walters Gardens, Inc. in Zeeland, Michigan.