Fertilizing roses

My roses are already showing leaves, so I fed them yesterday. I gave them a mix of ammonium, iron, and magnesium sulfates (listed in declining amounts).

Tx, David. How is this different from commercial rose food from nursery? I don't have one handy to compare formulae.

TIA

HB

Commercial fertilizers often contain phosphorus, which is a waste of money and a potential pollutant. The problem is that phosphorus -- which promotes flowering -- does not readily dissolve. Instead, it must be placed where roots will find it. That is why I always place either bone meal or super-phosphate in the bottom of planting holes when planting something. Also, every 5-10 years or so, I take a piece of steel rebar, poke holes about 1-2 feet deep in the root zone of my roses, and then fill the holes with super-phosphate.

Furthermore, roses prefer an acid soil. That is why I use sulfates. Most commercial fertilizers are relatively neutral.

Despite all that, I do use a commercial fertilizer. I feed my roses monthly from the time new shoots appear after pruning until late October. After the initial feeding with ammonium, iron, and magnesium sulfates, I alternate between only ammonium sulfate (nitrogen) and a commercial fertilizer that contains a systemic insecticide. The instructions for the commercial fertilizer say to use it every 6 weeks, but I only use it a full two months apart. I never see aphids, spider mites, or bark borers.

Most informative, tx.

Two further q's:

Why would (commercial)) phosphorus be a "potential pollutant".

Which commercial fertilizer avec insecticide do you use?

TIA

HB

HB

Because the phosphorus disolves so slowly, it is more likely to wash away and enter streams and lakes. Eventually, it will disolve and then cause excessive algae growth. As the older algae die, their decomposition consumes more oxygen than the living algae produce, leaving insufficient oxygen for fish and other aquatic animals.

I use Bayer 2-in-1 rose and flower care. It contains Imidacloprid, which should be used sparingly since it is quite harmful to bees. Although not approved for use on edibles, studies indicate it is harmless to birds and mammals (including humans). Thus, I use an Imidacloprid drench on my peach tree to prevent flat-head bark borers; but I use it only after the tree has finished blooming. I also use Imidacloprid on my dwarf citrus to treat leaf miners, but only after I see actual leaf miner damage and not when the trees are blooming or about to bloom.