Questionhello lynnette, could you answer the following short questions for me?
what's the best way to water rose trees at this time of the year (april)?
my bucketful of water for the whole lot, once a week' seems to work but
i wonder if i'm draining the soil of the roses's nutrients.
on new roses planted a few months ago, some stems look diseased
whilst some others have diseased tips or die back, since they are mainly
bare stemmed and only say 1 foot high, do i cut off the bad growth, or does
growth mainly come from the base than the tip of the stems?
what are the best ways to tackle black spot on some floribundas- icebergs
i've only just sprayed them with anti fungus on both sides of leaves, but have
heard of sulphur rose.
an old english rose is already growing too high for the size of our garden.
if i had pruned them down more in the winter, they may have grown even
higher. how may i reduce its size to fit our garden?
my garden is in eastern england- you may remember me from previous questions
thankyou and good wishes
philip
Answer
New cane killed
In regards to nutrients draining out of the soil. It all depends on what type of soil you have in your garden. If it is mainly sandy type soil, then that makes it easier for the chemicals to drain through. Clay soil really holds the water, even too long. Most soils will hold fertilizers long enough for the roses to use it up. Roses don't take nutrients up such as commercial fertilizer, until the temperatures are above 70' Always bear in mind the soil only needs to be damp but not wet, so at this time of the year you may not need as much water to make the soil stay damp.
You must cut down to the healthy green growth because that black is a fungal infection an the type of spores that are causing it, don't mind the cool weather. When the weather heats up they are killed. So they will continue to kill the insides of the canes until they are killed. The best and strongest growth always comes from the base of the stems but you don't always get that type of basal canes because some roses are not genetically programmed to make growth that way. Keep in mind, rose canes will grow back from only one inch left at the base. If you are always getting black marks and dieback on the roses, it may be the nursery you bought them from or in your area, you may have to mound them up when you plant them for protection. Spring roses are dug up in the fall and overwintered in temperatures just above freezing. If this isn't done correctly you will get problems like the photo of when buds are killed by a nasty frost on the canes. Cut below those black marks.
The best method of killing black spot spores that have overwintered, is to spray the roses with what is called in North America, dormant oil and sulphur spray. It is mainly used on fruit trees but there are instructions on the package for a rose spray. The left over sulphur tends to discourage fungal spores from growing on the rose bushes. Although I love Iceberg, it has had it's day commercially and now is very prone to blake spot.
You prune mainly in the spring to encourage a rose to put out vigorous new growth, but you prune in the middle of summer to keep the bush down to a smaller size because it it mainly in the spring that a rose makes very vigorous growth. If you prune the rose bush now you will mainly encourage vigorous new canes which will be longer than if you didn't prune it. Wait until after the first flush and then cut the rose back 12 inches shorter than what you want it to be because it will put out new growth which should then grow to just about the size you want. If you want this size and the rose tends to grow larger, you will have to summer prune every year. Summer pruning works well for extra long canes on roses too. Just cut the long canes back even with the other canes. Hope this helps.
