Why pine bark mulch is bad for roses

Roses and plants in general love a good thick layer of organic mulch. It keeps the soil moist in hot dry weather and it turns into humus as it starts to decompose. However, there is mulch and there is mulch, not every mulch is suitable for roses. Research has shown that a mulch layer of pine bark is bad for newly planted roses and even for adult ones. Pine bark starts to deplete nitrogen from the soil which causes young roses to really struggle, in essence it starves them to death. Even older roses will struggle.

So a mulch layer of pine bark has to be avoided. If you love pine bark for its esthetics you can however work around the nitrogen issue. You give your roses a thick layer of composted manure or leaf compost and on top you put a layer of pine bark. The manure compost will form a barrier between the soil and the pine bark so it can't extract the nitrogen directly from the soil and our roses. It will however extract the nitrogen from the manure or leaf compost. 

Better is to look for alternatives for pine bark. There are plenty of good esthetically pleasing alternatives which will ensure your roses to grow even better.

Pine bark chips deplete nitrogen from the soil