Yeah, I think you might have problems trying to encourage 'bushieness' by pruning banksia, I've had some success with the dwarf varieties but not with those mentioned. I have both of those and do prune them but never back to bare wood and only to shape.

There are three possible causes: 1. salt damage caused by water being too salty which could be at this time of the year depending on its source, or fertilizers 2. poor drainage 3. fertilizer containing too much phosphorus. A possible solution is to deep water, flushing the salts from the root zone, allowing the soil to dry a little before the next watering. Deep watering less often is preferable to frequent light waterings. Hold off the fertilizing until autumn, only use one that is suitable for native plants with minimum phosphorus. If the drainage is an issue plan to dig the plant up and replant in a raised mound. Pick a cooler run of weather to do this.

Check this site. Here's a comment they make about yellowing of the leaves: "B. marginata requires low maintenance. They hold their shape very well. Lignotuberous plants can be pruned hard, whereas non-lignotuberous plants should only be lightly pruned. If foliage begins yellowing, apply chelated iron."

Sure hope you all are right! We had a week of bitter cold, one night was 3. Others were 12, 19 and in the 20's. What worries me is that I saw some splitting of canes and didnt see any kind of green on them. They are established bushes and line my driveway, just fabulous in the spring. But if they are alive at the roots.......and will return maybe all is not lost. I also worry about my glorious Crepuscules too. I have been pruning roses, starting with ones in pots. On most, I can see about an inch of green cane.......they are just nubs [and I have waited until I am sure the other cane is dead]. People in the north keep telling me they will come back......it is just hard to look at these pitiful things and believe they can become a bush with blooms again. I will say I am pleasantly surprised at this - the David Austin roses every one seem to have green canes.......esp. Mary Rose. Even a small potted Vanessa Bell. I have been amazed at the cold tolerance of these roses. Emily Bronte is the only one that looks like it will have to be taken back to 1-2". The wonderful Bucks of course are every one thriving. And a new one, while I am at it, I would recommend is a small landscape shrub called Coral Miracle - new last year. The cold didnt touch the canes on this little beauty. I like it in pots.....it came through like a champ, pretty color. Ya'll try one if you can find it for sale. I will just leave the Lady Banksias alone for now......going to really hurt to cut off that beautiful arching growth but if the roses are alive, as you all have given me hope for, they will grow fast and bloom next year. I may be able to find some one gallons with buds and plants those beside the big pruned roses just to see these gorgeous primrose yellow blooms.......thanks ya'll for the help. Judith