Epsom salts is usually applied to the soil (and watered in), to correct a magnesium deficiency which causes a yellowing and dropping of the leaves. If this doesn't happen to your roses then you don't need to do it. I grow roses in fairly sandy soil and the leaves of some, not all, have a tendency to yellow and fall in late spring. A teaspoon of epsom salts at this time seems to rectify the problem. Some books recommend a larger dose, depending on the size of the rose and, some books say to do this at prunning time. But I have read that too much can damage the soil, so I would say don't apply it until if and when you need to.

As for the rose fertilizer, which puppy will probably like just as much as blood and bone, just follow the directions on the packet. Some fertilizers are not for bare rooted or newly planted roses, so do check this if you have new babies. Remember, roses are pretty tough and, other than not watering them, there's not much you can do to harm them.

Wattleblossom, apply rose food in late August and then again in February, which means every six months. Slow release fertiliser is recommended becaue it releases nutrients slowly and won't burn your roses.

Epsom salts (which contains magnesium sulphate) you can add few times a year. I suggest you to first dillute Epsom salt in a water can (1 small cup per 5L), and then water your plants.

But do not exaggerate -- if you're not sure what to do, you can perform soil analysis first: for example, you can buy pH test kit in every Bunnings store. pH test will tell you how well your rose can reach for iron, magnesium and other trace elements which are necessary for photosynthesis.

if pH is too high (>8, the soil is alkaline, which is common for sandy soils) then your rose will have problems extracting magnesium and iron. Lowering the pH is necessary then and that's where adding Epsom salts will help a lot! Because Epsom salt contains sulphur as well, it will lower (make it more acidic) the pH of your soil too. Ideally, roses love pH to be 6.5 - 7.0.

To lower pH you can also use aluminium sulphate or elemental sulphur -- you can find it in azalea section in every gardening centre, because azaleas like soil with the low pH (All the same, if your soil is too acidic, you will wan to raise the pH by adding lime. In both cases all you want to do is try to introduce some natural balance in your garden soil and make roses happy. If they live balanced life, your reward will be great.

Here is a link that might be useful: More info about pH soil testing and fixing

OK - so we have fairly acid soil - I add lashings of lime every year for the irises. I will keep the epsom salts for the bath :-)

If you do have low ph and associated mag. deficiency (gardenias are good indicators)then dolamitic lime is the best option as it does provide some magnesium while increasing ph to a more appropriate level.Be careful not to confuse magnesium with manganese.Magnesium becomes more available at higher ph while the opposite applies to manganese.All plants use relatively large amounts of mag. and roses use more than average.The cheapest way to determine if your roses require further mag. post liming is just to throw a little epsom.s around them at various times of the year. If growth appears to improve ..great.If not...don't worry be happy.But your chances of damaging plants/soil with small applications are remote to say the very least.
Hoping for greener roses.Thrip