This week I answer readers' questions:
Q: My rhodos are getting dried-up leaves and buds, so I cut them off. Will this kill the rhodo? How do you care for rhododendrons?
A: Whether your rhododendrons will die from the pruning you did could depend on how much you cut off. The rule of thumb for pruning is never remove more than one-third of your tree/shrub at one time. It's best to space severe pruning over several years.
Generally, most rhododendrons handle moderate pruning well. This is especially true if your rhododendrons are well established and most of the branches remain with leaves that are still green. But after pruning, flowering may be reduced the following year.
If the leaves you removed were brown and crispy, the plants could be badly dehydrated. This is even more likely if they were growing in pots. The ideal situation for containerized rhododendrons is growing in very large containers in a mixed sun/shade situation where sunshine gives gentle light and warmth and their soil is mulched to conserve moisture.
But even growing in an outside garden, rhododendrons still need watering in times of drought
Summer last year was very hot, dry and long and it could be your rhodos didn't get enough water. If they were in pots, watering may not actually moisten them. Sometimes, soil in pots can become so dry it shrinks away from the sides of the pot. When this happens, water can run down the inner sides of the pot and away.
Another issue with containers is that fierce heat in summer can attack plant roots through the sides of the pot (this happens also with cold in winter).
There are two possibilities for the dried-up buds. Dehydration is one.
But they could also have a fungal disease called bud blast. Infected buds are brown, hard and don't flower. As spring continues, the bud surface develops black, furry-looking fruiting spores.
These buds need to be removed before they can continue the disease into another year.
This infection is thought to be spread by leaf-hoppers. Check the underside of your rhodo leaves in late spring/early summer. If you see little white crawlers, this will be the larval stage of leaf-hoppers.
Insecticidal soap will kill them on contact. But like all killing sprays, it can kill beneficial insects too - and the person applying it needs to be cautious and follow instructions.
Q: Is it time to plant tomato plants outside yet?
A: When temperatures are following their normal pattern, mid-May is about the right time to put tomatoes outside. Until then the nights are cold and tomatoes may not die, but they don't grow and take a while to recover when the weather does warm up.
If you have your tomatoes in pots and have a sheltered spot for them, by a south or west wall, I suggest you put just one pot outside and see how the plant does.
If it grows normally and looks healthy after a few days, your others could follow. But keep watching the weather forecasts for a couple of weeks in case an unexpected cold snap is predicted.
Anne Marrison is happy to answer garden questions. Send them to her via [email protected] It helps me if you can mention the name of your city or region.
