This week I answer questions from readers: Q: I have several boxwood that I hope one day will grow together and make a small hedge. Most of them have some part of the bush now turning orange in colour. It started last year and is getting worse.
I can't see any bugs or webs on the bush. What is wrong, please?
A: Orange leaves are a symptom of the fungal disease boxwood blight. This started in England, moved to the United States and is now in B.C. Sad to say, it's considered incurable.
The orange leaves will die and gradually fall off. Meanwhile, more leaves turn orange.
Boxwood blight can spread around neighbourhoods by wind and rain (like other fungal diseases).
Fungicides can prevent it, but they can also mask it so that a bush may be infected but it seems to be OK. To be successful with fungicides, you have to cover absolutely all the bush, including the stems and undersides of leaves. Unfortunately box is so dense, this is almost impossible to do.
There are other shrubs that might make a good replacement hedge. These include Japanese holly (Ilex crenata), an evergreen shrub that produces masses of white flowers followed by black berries. It is very hardy.
Dwarf rhododendrons make a lovely hedge. The Yakushimanums usually have pink buds and pink or white flowers. They're very easy to get.
Cryptomeria japonica (Globosa nana) is a dwarf, very rounded evergreen.
Dwarf salal is another possibility.
You might want to wait a bit and see how fast the blight moves, but it has the reputation of being hard to deal with. Sarcocca can also catch it along with some other boxes like Buxus microphylla. It can lay dormant in fallen leaves of box for five years.
Q: My neighbour had a new lawn put in and there are mushrooms growing here and there near the property line. It is northfacing and not helped by my neighbour's three-storey house.
How can I prevent the
mushrooms from spreading onto my side of the yard? There is no fence there.
A: It's very likely your neighbour's topsoil contained commercial mushroom compost from a mushroom farm.
If so, they're most unlikely to become established in the neighbour's lawn or yours.
But to be absolutely
certain, you could install an edging all the way along the property line. It should be deeper down in your soil than the
depth of your neighbour's new soil. A garden centre would be able to sell you suitable edging.
Q: Can I stop fertilizing my petunias and geraniums now?
They are in containers. I used the Shake and Feed just once when they were planted in May and they looked gorgeous.
Does it just need to be used once a season as it's quite expensive?
A: Shake and Feed fertilizer lasts about four months, so you won't need any until the end of September. By then nights are colder and annuals are getting older and ready to be composted.
The best thing you can do is hold off applying it again. Shake and Feed is intended to last a whole season.
Anne Marrison is happy to answer garden questions. Send them to her via [email protected]. It helps me if you add the name of your city or region.
