One possibility is to selectively prune back about a third of the stems/branches, about 6-18", in the mid-spring, as you see new growth. This should cause delayed flowering on those stems, and extend the season for you. If you REALLY wanted, you could do the same on another third a few weeks later, but that may be overkill. And this will work only if the spirea flowers on new growth. If it flowers on old growth, it won't work.

I have a related question. I bought a Christmas Cactus that's in full bloom around Christmas for my mom. she over watered it and all flowers fell right away, but the plant is okay. I asked my mom to keep it in a bright place but away from direct sun light and keep it dry. We are in chicago and it's still very cold. I wonder when can we expect it to bloom again. Will it bloom twice a year, and how long does the bloom usually last? Am I doing the right thing to promote the next round of blooming?

Background: I bought a very small Valencia Orange from Stark Brothers two years ago (along with an order of fruit trees). First year was strickly indoors, not the greatest growth. This last summer I moved it outside. I purchased a lemon and a lime from Home Depot during a trip to CA (they had Four Winds tags on them) and brought them back to Utah. Care: They seemed to be doing okay, and I fertilized all with a citrus fertilizer when I got home in August. I moved the orange to a larger pot at about this time, using a pot I had similar in size to the ones from HD/Four Winds, but the orange isn't nearly as large, but lots more leaves. When I moved them into a sheltered area (no direct sun) to prepare them for winter, the lemon lost all of its leaves - may have also been a lack of watering issue as well. At any rate, I moved them to the garage next to a north-facing window and the lemon produced all new leaves. A few weeks later, the lemon and orange produced quite a few blossoms. Of course, the blossoms quickly dropped, but the orange has continued to blossom with one or two here and there after I moved it near a second floor south facing window. Analysis: I thought the blossoms came because of the changes in settings (cool/cold to warm) as if it was going into spring? At any rate, it was my first use of a citrus fertilizer and the first time that the orange had blossomed in the two years I've had it.

i cut my Hibiscus back to 3" from the ground last winter. Stalks were about 3/4" round. I waited. All of a sudden in mid spring up shot new shoots. Now it about 5' tall , very heavy on it's self. No blooms yet. I water heavy regularly, here it is mid June & no blooms! Should I tie the tree up to a post or let it be on its own? Also, will I get blooms this year due to cutting all the way back last winter??? Please help someone!!