Streps don't do well here, so I'll have to rely on my rather faulty memory of growing them in other climates. Are you giving them good light, and feeding (lightly?) If memory serves, the leaves that have bloomed won't bloom again, so it is important to feed regularly--I fed with every watering--so they'll keep growing new leaves. You may, if you wish, take off the old leaves, especially if they're somewhat battered, as that may encourage the growth of new foliage.

Each leaf will give three to seven blooms depending on the variety and growing conditions. Once the leaf has put out as many bloomstalks as it can, it is finished blooming. The plant then has to rely on growth of a new crown. Therefore to keep a strep blooming, you need to encourage continued bloom on labouring leaves and encourage new growth.

The amount of the bloom you get will also depend on the variety. With the right growing conditions, some will bloom all year while others will only bloom in the spring.

I fertilize year round with half strength 10-15-10, repot regularly and my streps have their heaviest bloom in the spring, another flush in the fall and periodic bloom in between.