Impatiens/ Busy Lizzies Not Flowering

[bond]

Last year Lizzies in my window box thrived all the way through to about October flowering profusely. This year I had initial blooms, but now all gone and no more flowers just lots of green leaves. It is in a pot (inside the window box) and routes are growing out, but I thought they liked being slightly pot bound. Why is it not flowering any more? Its not too dry or too wet...should I repot it? Thanks.

[Buenchico]

Repot them and, importantly, check that you've got them in a well-drained potting medium (with decent 'crocks' in the bottom of the pots). Lots of websites suggest that 'moisture stress' (caused by poor drainage) can be a problem. e.g.
http://homeguides.sfgate.com/impatiens-plants-buds-but-wont-bloom-80690.html
Others, however, also suggest that the excessive use of nitrogen-based fertilisers can be a problem. e.g. http://homeguides.sfgate.com/impatiens-dont-bloom-65875.html
The issues might not be unconnected though, as nitrates can build up in poorly-drained potting composts.

[Ann]

A few years ago all Busy Lizzies suffered with Downy Mildew disease which caused the flowers to drop off and just leave bare stems, a sorry sight indeed. Nobody grew them for the next couple of years and this year it was reported that the disease was eradicated.

No - mine have died just the same as before so this dreadful plant disease is still around.