A CONSULTING ROSARIAN ANSWERS YOUR QUESTIONS…
Question: Why do many rosarians use Epsom salts on their roses?
Answer: Each year in February or early March I come home from the drugstore with a cart full of Epsom salts. Why? Do my feet really hurt in only those months? No! I’m stocking up on Epsom salts in order to add it in my roses’ spring diet. Let me explain.
Epsom salts (magnesium sulfate) applied to rose bushes in the spring encourages the bush to produce those welcome basal breaks. Basal breaks are new canes which develop low on your plant near the bud union, (these are not suckers which will grow below the bud union). Of course, these new canes are highly desirable. And, Epsom salts really work. I have had good success getting new canes with its use.
Epsom salts works best when the plant has already been fed some nitrogen. So, when I begin fertilizing in March, after my roses have leafed out about 4 inches, I start feeding with sulfate of ammonia 21-0-0 the first week. The third week of March I apply the Epsom salts. As the season progresses, I continue with the Epsom salts but gradually cut back on the amount.
There are many different fertilizing schedules advocated by prominent rosarians – each slightly different. However, the following schedule has worked well for me for several years. It comes from Rayford Reddell, a rose expert who has written several books on rose care and is owner of Garden Valley Ranch a large nursery in Petaluma. I’d like to share it with you. It is as follows:
Gourmet Diet for Roses
By Rayford Reddell
(Recorded by Fay Cook)
March & April
First Week: Sulfate of Ammonia
(31-0-0, 21-0-0, or 15-0-0). 1/3 cup along drip line – well watered in.
Third Week: 3/4 cup Epsom salts (MgSO4) well watered in.
May & June
First Week: Balanced granular fertilizer
(10-10-10, 15-15-15, or 20-20-20)well watered in.
Third Week: 1/2 cup Epsom salts per bush well watered in.
July & August
First Week: Balanced fertilizer (as above).
Third Week: Fish Emulsion 2T per gallon water, use 2 gallons per bush.
September & October
First Week: Granular, water soluble 0-10-10
(Encourages no new growth, but continued blooms and hardens wood for winter.)
Third Week: Fish Emulsion (same as July & August)
No fertilizers after Halloween
If your roses still seem hungry, in spite of this hefty diet, fertilize to your hearts content with additional shots of fish emulsion, which is not only thoroughly organic, but also incapable of burning plants.
(The above fertilizer schedule is for large or average size plants. For minis or smaller bushes, I use only 1/4-1/3 of the above amounts. If in doubt – less is best.)