Native to Australia, scaevola is grown as an annual but is a perennial by nature. It produces a tough, bushy plant with a mounding and trailing habit. It’s free flowering, has excellent weather tolerance and is self cleaning, so there is no need for deadheading. Flowers are a distinctive fan shape produced on short terminal spikes. The plant is quite heat and drought tolerant and ideal for low-maintenance situations.
Scaevola is a day-neutral plant. Modern breeding has made advances in making plants flower earlier and creating a more controlled habit. Suntory, which recently introduced the Surdiva series, offers production advice:
Rooted cuttings should be potted up as soon as possible into pot sizes 4 inches and larger, using open, free-draining growing media with a pH of 5.3-5.7 and incorporating a balanced fertilizer. Aim for an EC of below 2.0. Scaevola are generally iron-inefficient plants.
For the first couple of weeks, the crop should be grown at temperatures of 60-65°F. This will help with root development. Do not over water at this stage. After two weeks, raise the temperature to 65-70°F.
The crop may require pinching to encourage the right habit and breaks to get a bushy and spreading plant. Use one plug per 4-inch pot.
The crop should be watered uniformly throughout its life using a balanced liquid fertilizer of 110-125 ppm. Water plants prior to wilting. Allow the substrate to dry out between waterings. This will reduce the risk of root rots.
Extra iron applications may be required to promote good leaf color. Apply as iron sulphate drenches (avoid foliage contact) or iron chelate sprays or drenches of EDDHA.
Purpling of the foliage can be a result of low phosphorous and is more predominant in some colors. Moderate or high levels of phosphorous can cause yellow-red coloring in older foliage.
Maintain substrate EC of 2.0. Allow plants to dry between irrigations, as they are susceptible to overwatering.
The use of growth regulators on this crop is not necessary, but pinching plants can encourage the correct shape and act as a form of growth control. B-Nine (paclobutrazol) drench and uniconazole work well on scaevola.
4-inch pots–six to seven weeks from liner
6-inch pots–seven to eight weeks from liner
10-inch pots–12-15 weeks, three liners
4-inch pots–one pinch
6-inch pots–two pinches
10-inch pots–two to three pinches
Less pinching is required when plants are grown cool.
Mites (Tetranychus urticea)
Botrytis cinerea (gray mold)