Anyone know anything about box/buxus?

[GrouchyKiwi]

We've got a couple of box plants in pots. The outside leaves have all gone yellow, but the inside ones are still green. Is this because of being too exposed? We get quite strong winds in the front of the house, where the plants used to be. I've now moved them to a more sheltered spot, but I'm wondering whether I can resurrect them, or whether the yellow means I've managed to kill them. I'm not much of a gardener.

Awww, it might not be your fault kiwi! There are lots of possibilities, depending on where you are in the world:

• Sun scorch! (or wind scorch).
• Really low temperatures can make leaves go temporarily a bit yellow. (Is it cold right now with you?)
• Dessication (has it been watered enough?) or waterlogging (too much water on heavy, claggy soil can, confusingly, produce similar symptoms to too little)
• Pet wee (my cat really used to love weeing on my box balls, which produced big yellow patches. I had to defend them with sticks so they became box hedgehogs for a bit).
• Box blight (though - good news - this tends to leave bald patches rather than to scorch the outside only).

Have a really good look at the leaves. Are they the right shape or have they gone cup shaped (a sign of suckers)? Are they smooth or unusually bobbly (a sign of leaf mining midges)? Are they all dotty and mottled (a sign of spider mite)?

Don't worry Kiwi I'm sure they'll recover! I think Shove has already covered it all but I am leaning towards frost damage.

Have you recently pruned them? You can always do a soil test to see if the soil is too dry. Just stick your fingers into the soil a couple of inches and if it's moist then the soil isn't too dry.

From my experience it's always a good idea to top dress them with some new compost, one that contains a slow release feritiliser is best. The problem with keeping Box in pots is that you have to add nutrients to the soil at least once a year.

Could also be potassium deficiency..
benlannoy.com/box-pyramid-buxus-sempervirens/

Thank you for the advice. I'll get some potassium and try that.

We're going to plant them, once we've decided where to put them. It's a new build house so it's very blank.

also if they are in pots have you repotted at all? they go a sort of bronzy colour if they need food so when you plant them out make sure you either mix in a lot of compost or add some slow release feed to the surface - they bounce back fast in my (limited) experience.

Have repotted the plants with lovely soil and plant food and moved them into a more sheltered spot. They are not recovering very well, I think.

Is it potassium nitrate that I should get? I really do know nothing.

This makes me feel like I'm buying drugs...

www.amazon.co.uk/1kg-POTASSIUM-NITRATE-HIGH-PURITY/dp/B00TVM3X4I/ref=sr_1_1?s=outdoors&ie=UTF8&qid=1440406557&sr=1-1&keywords=potassium+nitrate

Kiwi are you in NZ? This will affect my advice.

No, in Scotland. :)