Pure urea and uncomposted animal manures can also burn. Steer manures often have high salt concentrations, so it is best to avoid them. The key to whether roses need or have too much nitrogen can be determined by looking at the leaves or the plant. Luckily the deficiencies can be quickly reversed. Oxygen deficiency is similar, but adding nitrogen will not correct it.
Excess nitrogen can look like a deficiency.
The new leaves are chlorotic, which is also a sign of iron deficiency. But, iron will not correct it. Also, foliage tends to be large and excessive in size. For some sensitive varieties, high nitrogen will produce vegetative centers, where the bloom looks as if it swallowed a bloom of Green Rose . Lady Sunblaze , The Temptations and Marchesa Boccella are examples of nitrogen sensitive roses.