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terri_zone5

too much aluminum sulfate

terri_zone5
18 years ago

Help! I wanted to adjust the ph of my soil by adding aluminum sulfate for more blue blooms on my Endless Summer Hydrangae, but I used too much and now the top growth is browning and dying. Have I killed it? About 1/2 the shrub is gone and I'm not sure about the rest. Is there anything I can do? Any help would be appreciated.

Hydrangae killer

Comments (31)

  • gardengal48 (PNW Z8/9)
    18 years ago

    The effects may be irreversible. Flushing the soil with lots of irrigation won't hurt and could help, however aluminum toxicity can damage root systems to the point where they are permanently compromised. FWIW, aluminum sulfate should be used very cautiously and with strict adherence to label directions. I prefer to increase soil acidity through less potentially harmful means - argicultural sulfur, fertilizing moderately with nitrate-based fertilizer with an NPK ratio of 5-1-6, amending the soil with peat or even mulching well with spent coffee grounds can provide similar and safer results.

    It should be noted that soils tend to buffer significant changes in soil pH, so if your soils are neutral to alkaline, attempting to alter pH significantly is a temporary measure at best.

  • terri_zone5
    Original Author
    18 years ago

    GardeningGal48,
    Thanks for the help. I think you're right -- I cooked my
    ES. I thought I followed the directions, but, obviously, got it wrong or I wouldn't have this problem.

    Now, how long is the soil compromised? I think I'll leave the hydrangae to see if it will come back next Spring. Not hopefull, but it won't hurt anything to try. If it doesn't come back, I would like to plant another Endless Summer in the same place. Do I need to do anything to the soil? I know that even if you try to acidify the soil, it does revert back. I just don't know how long that would take. I ususally work compost into garden soil when I plant, but don't know if I should remove part of the garden soil & add compost trying to reduce the Aluminum Sulfate. Any ideas???

    tc

  • yellowgirl
    18 years ago

    Hold on Terri,

    Did you by any chance get any of the alum sulfate on the leaves of the plant? Doing so could cause this kind of damage to the leaves but not necessarily harm the plant as a whole. (learned this the hard way more than once). It should only be applied to the soil and never touch the actual plant. Look for other signs of life on the plant like new leaves, green stems, etc. If so, be patient, it will come back. I have used some pretty hefty amounts on some plants (not advisable) but luckily, I haven't killed one yet.......yg

  • terri_zone5
    Original Author
    18 years ago

    Hey, YellowGirl. Thanks for the reply.

    I didn't put any on the leaves. It was granular & I worked it into the soil. I am going to leave it until next Spring to see if it comes back.

    Any ideas about what I've done to the soil? Should I get a soil test done in the Spring? Was thinking that would probably be the best, as then I'll know if I can plant there again (Assuming the ES dies).

    I welcome any info/ideas.

    tc

  • orchids41
    18 years ago

    So what time of year do you apply aluminum sulfate and how often? And do you just sprinkle it on the soil around the plant or do you dissolve it in water first? IMWTK (Inquiring Minds Want To Know).............judy

  • terri_zone5
    Original Author
    18 years ago

    Judy,
    In the FAQ section of this forum, it says to mix a solution of 1/4 oz of aluminium sulphate and 1/4 oz sulphate of iron with 1 gallon of water to acidify the soil and turn the flowers blue. It also says to apply up to 2 gallons in Spring and Fall. A stronger solution can have a negative effect, so do not exceed recommended dosages. To encourage pink, add lime.

    I wish I had checked before I put my aluminum sulfate on. Probably wouldn't have kiiled my shrub!

    Good luck,

    tc

  • donna1952
    18 years ago

    I am glad to read the comments on Aluminum Sulfate as it seems a bit confusing. Hydrangeaselect.com says A.S. should be applied 4-6 months before color change takes place. They say 2 Tablespoons of A.S. to a warm gallon of water - well dissolved and pour 1/2 gallon on the soil (avoiding leaves) then wait 2 minutes and pour the rest down onto the soil. Repeat every 20-30 days until desired flower color has been reached. Can you imagine walking around an acre with a bucket of warm A.S. to each of 16 plants - each about 6' tall and wide? There must be a better way to do this. And, I have no "warm" water outside! No local garden centers today had ever heard of Aluminum Sulfate! DUH! They recommended Azalea and Rhodie fertilizer to change the color. If applying A.S. dry (if I can find any) - how much would a 6' plant take? I want to change from whites with light blue to a dark blue or purple. I have Dolomite Lime for the pinks and reds - so I am in business with that. Thanks for any help. Donna

  • hayseedman
    18 years ago

    You need a couple of long hoses, I think. A couple of 50 footers hooked together, maybe.

    The warm water adds nothing in my opinion. I'd just forget about that.

    Adding dry aluminum sulphate to the top of the soil and waiting for the rains to wash it down means you're probably gong to be having a very high concentrated amount at the top and nothing down deep. Spells trouble, I think. When I apply it, especially to my potted plants, I drench the soil completely first with just water and then apply a drench with a couple of tablespoons in a gallon of water. Some of my gardening is in very alkaline soil and I'm not so sure that any of my efforts really make a really significant difference.

    (I bought some cheapo hoses at Walmart last month for something like 5 dollars for a 50 foot hose. For twenty dollars you could get enough hose to reach any point on your property. )

    I would bet that the most important time to be adding Aluminum Sulphate is early in the spring before the plant starts growing.

    Good luck. Hay.

  • yellowgirl
    18 years ago

    Most garden centers don't sell AS...I have to buy mine at a feed supply store. Azalea/Rhodo fertilizer is good for hydrangeas but won't change the color from pink to blue and nothing will change a white as they are (as a rule) not ph sensative. Some, like Hollytone and Osmocote w/soil acidifers will go a long way in helping to boost or maintain the blue once you get it.

    I have very sandy soil so I have never mixed AS with water. I just sprinkle a handfull around the drip line and water it in. (I do this with potted ones as well.) In doing so, I have at times inadvertently dropped the powder on a leaf or two causing the almost immediate browning of those leaves. I agree with Hay about the timing. Before the buds break is best. My experience has been that for the most part, only future blooms will be affected, existing blooms stay pretty much what they are, colorwise. If your soil ph is very high, adding AS (by whatever method) is a process that would have to be repeated over and over as the effects don't last and your soil will always revert back to it's normal ph. I also throw a palmfull in the hole when planting. Again, I have sandy soil, so much of what I put in the ground seeps through rather quickly ($$cha ching$$) therefore I am not recommending this method for everyone, I just know it works for me.....yg

  • gardengal48 (PNW Z8/9)
    18 years ago

    Since I am adverse to adding chemicals to my garden and aluminum toxicity is a fine line when attempting to alter hydrangea flower colors, I employ other methods. I'd also disagree that Rhodododendron and Azalea fertilizers (or those labeled for "acid-lovers") will not be effective in altering soil pH. Nearly all will contain amounts of typical soil acidifiers, agricultural sulfur being high on the list, specially those labeled as organic formulations (which I lean heavily towards).

    Altering soil pH significantly or permanently is an exercise in futility as all soils contain buffering agents that limit the degree to which this can be accomplished and for how long.

    I'd like to quote from Dan Hinkley, a local horticulturist and plant collector of some reknown and founder of world-famous Heronswood Nursery, which has an extensive collection of hydrangeas:

    "Please note that many hydrangea cultivars are stable in their color and will not change or change only slightly, if the pH is adjusted. It is also important to understand that in both very acidic or very alkaline conditions, it is virtually impossible to modify your soil pH to a degree sufficient to change the color of any hydrangea. In these instances, you can either choose to grow them in containers, where you have total control of the soil pH, or be content with the colors that result.

    A correct fertilizer program for your hydrangeas will not only assure more robust and healthy plants, but aid in color intensity. For best blues, apply a nitrate-based, rather than ammonium-based fertilizer with an NPK ratio of 5-1-6. Even better blues can be achieved by a yearly application of aluminum sulfate, available through garden centers - follow application rates carefully! Avoid using bone meal or superphosphate when planting. For best pinks, use a nitrate-based fertilizer with a NPK ratio of 5-2-2. Or if all of this is just too complicated - just plant 'em and enjoy 'em."

  • hayseedman
    18 years ago

    How did aluminum get such a bad name?

    I have yet to meet someone who doesn't have it in their mind that adding aluminum is a risky business.

    Why do you think it's so bad? You meaning whoever is reading this at the moment. I bet that it goes back to hearing that there are some plants and fish that are being decimated in our natural environment by the aluminum that is finding its way into our streams and ponds, especially in the east of the US. Or is it because of the association we have with Alzheimers and aluminum found in brain?

    Hasn't link to Alzheimers been discredited at this point?

    And the real problem, as I understand it, with the aluminum killing off the fish in the streams and ponds is real. BUT, this is not from someone adding aluminum to the soil or anything like that. Rather, it comes from the soil being constantly hit with the acid rain that we get, especially here in the east. Aluminum is a very abundant element in our soils and is mostly locked up with other elements so that it doesn't cause a problem. Add acid to make the soil acidic and you release some of that aluminum.

    So, adding aluminum sulphate to the soil or adding anything to the soil that makes the soil more acidic will have the same effect: you free up aluminum.

    I think it's interesting that the amount of aluminum in aluminum sulphate is about the same as the amount of aluminum in granite. No one would get too excited about adding a couple of tablespoons of granite dust to their soil, but they would think twice or three times about adding aluminum sulphate. I bet that most of the aluminum in aluminum sulphate gets locked up really fast (or else why doesn't it work so well to blue up our hydrangeas when we try to do it in native soil)

    And if you're still afraid of aluminum sulphate, beware of some Stella D'Ora baked goods. I think it was one of their breakfast toasts or something like that. There it is on the label: flour, sugar....aluminum sulphate...

    Hay.

  • yellowgirl
    18 years ago

    (smile)....yg

  • gardengal48 (PNW Z8/9)
    18 years ago

    The issue isn't about aluminum toxicity in waterways or contamination of fish and wildlife or even the effects on humans (although I'm not sure I'd dismiss that out of hand), but rather the effect OVERAPPLYING aluminum sulfate can have on plants. Read up on your soil chemistry - excessive use of aluminum sulfate has the effect of a rather abrupt, if temporary, acidification of the soil. The more acidic the soil, the more mobile the aluminum and if a little is good, a lot is not necessarily better. It doesn't take huge amounts to produce toxic effects in plants. Apply acccording to label directions - they are there for a reason. And since aluminum is indeed present in most soils, why run the risk? Just adjust pH by adding granulated agricultural sulfur or some other soil acidifying agent and let the naturally present aluminum do its work.

    This is not some old wive's tale but a verifiable soil chemistry phenomenon with the ability to produce real problems for plants. Even HydrangeasPlus cautions about the overapplication of aluminum sulfate.

    Here is a link that might be useful: HydrangeasPlus website

  • hayseedman
    18 years ago

    I hope I didn't suggest that you can use excessive amounts of aluminum sulphate and not have a problem. You will for sure have a problem.

    But I'm adding that I think many people have in the back of their minds that aluminum, per se, is more of a problem than it really is.

    Hay.

  • dsacco85
    18 years ago

    Vinegar will lower ph with out the Alum. Just dilute with water to a ph of about no less than 5.

  • ski_the_novice
    15 years ago

    I too killed my beautiful Hydrangea only it occured using a vinegar/water solution. In one day my BlueBoy turned to brown! I am going to try to salvage it with a lime dust. Otherwise I am now an enrollee in the school of "Let Nature Do It's Thing!"

  • ditaroman
    15 years ago

    I have been applying sporadically 3T of aluminum sulphate on my ES & Niko Blue and they are blue as can be. I soaked them with water after applying dry aluminum sulphate.

  • nude_gardener
    15 years ago

    read instructions and you will be OK.
    i use aluminum sulphate throughout the year and i have
    a very beautiful Niko and ES.

  • ski_the_novice
    15 years ago

    Ok so I thought I killed the Big Blue but it seems to want to live! Unfortunately with the exception of a single original leaf all others died. I placed a small amount of powdered lime around the base and it now is trying to turn green again. I do however have some very brown to black stalks and stems. Do I need to continue to add lime or what? I took a pic of before and after but I am not sure how to upload???

  • Gary M
    15 years ago

    Is ammonium sulfate better than aluminum sulfate?

    It is good to see Garden gal, Hey and Yg. I havent been around for a year or so.

    Gary

  • kyplantjunkie
    15 years ago

    Argh- I've shocked the s*** out of several of my ES- determined to get them blue this year- I applied AS one time too many, and the center of my shrubs croaked. They had black stems- after cutting to the ground, fortunately, they're putting out some new growth at the perimeter. So, hopefully, next year I'll have some blooms. I'll try using elemental sulfur next year-------following directions!
    Robin

  • chickenman6146
    14 years ago

    I have some untreated Nikko blues that are PINK!!! some treated with organic acidifier from Pettiti's garden center that are also pink,,, and some treated with Aluminum sulfate that are lavender/purple. I will retreat with Aluminum sulfate Al2(SO4)3 18H2O 3tablespoons per bush drip line, water in well, and keep blogging it results MF Medina, Ohio retired Cleveland public high school teacher, and OSU master gardener.

  • roseberri, z6
    14 years ago

    Chickenman, if you figure it out let me know! I'm in newark OH and I have been trying to get my ES blue ever since I got it!! It was a beautiful blue and when I planted it and tried all the methods to keep it blue, it continues to stay pink and lavender!
    roseberri

  • Carole Westgaard
    14 years ago

    The absolute best way to get blue hydrangeas is to move to Connecticut, Massachusettes, Maine, Rhode Island, Vermont, or New Hampshire. And probably Long Island. Vancouver Island is probably another good spot. Not sure about Washington or Oregon. But the East has the blues that will knock you out.

    Westy1941

  • monica33flowers
    14 years ago

    I use aluminum sulfate in the fall here in WI. I do add a bit more than I should but I also water it in really well.

    I then add just a small amount in the spring and if the frost doesn't get them in May I will always have the prettiest dark blue hydrangeas.

    I would show you a picture but my mother raided all of my blue hydrangeas for bouquets at her church.

    But I must say I always gets lots of compliments on the hydrangeas. Plus I'm on a corner lot so I have a lot of people that are walking that will stop in and ask me how to get their hydrangeas blue. BTW, mine are endless summer.

    I had 2 Nikko Blue's that never turned blue either. Just a really pretty bright pink color which I loved so I didn't try to change them. Unfortunately, after 5 years they didn't make it thru this past winter. A lot of perennials died this past winter....which was rather expensive and even killed two of my roses.

  • Vicki
    14 years ago

    I use Aluminum Sulphate several times a year liberally and have never had a problem with it and my endless summers still bloom only pink. Some soil is just that alkaline. Garden centers sell it everywhere around places like this.

  • char_35
    14 years ago

    I did not see a response to the question as to whether Ammonium Sulfate has the same effect as Alumminum Sulfate.
    I would recommend having soils analyzed before trying to change chemicals in ground. I had my garden bed soil analyzed at A&M this winter. My phosphate levels were in the high range. My plants were showing signs of Chlorosis. I added both Aluminum Sulfate and Ammonium Sulfate to the bed in slightly lesser amounts than recommended & one month apart. Then I took mulched leaf and pine needle clipping and applied them in a 2" layer and worked them and the Sulfates into the bed. (about 4-5" down). I've had no problems and plants are looking better.
    Not sure what color my Hydranageas will be. I'll let that be a surprise!
    If anyone is interested in obtaining the article from A&M on Phosphorus you can call them. (979-845-4816) To clarify they did not recommend the phosphates I did that on my own. I realize that this is going to take a couple of years to correct.

  • chasdog101_verizon_net
    12 years ago

    In the case of over applying aluminum sulfate, your plants could very easily develop aluminum toxicity, in addition to the potentially detrimental low pH accompanying this Al cation. To correct an aluminum toxicity without changing the pH, use a Gypsum CaSO4. If you would like to reduce Aluminum toxicity as well as raise the pH, (make it more alkaline), then use Lime, CaCO3.It is important that you know your soils' buffering capacity, or its resilience to chemical change, which is largely based on the cation exchange capacity of the soil. Also, before amending your soil with chemicals, know the current pH of your soil(you set yourself up for failure if you go in blindly without knowledge of your soil). Knowledge of the two above factors will help you determine the proper amount to use. To obtain this information for those of you who are not soil scientists, send a sample off to your local soil lab(look it up online). This process is cheap(only around $25), easy, and will ensure all your plants thrive in the proper conditions. Always remember, when you plant and grow your "landscape", always start from the ground up. The soil is key. PS ammonium and aluminum sulfate do not have the same affect, aluminum as well as H+ ions are considered acid cations, meaning they have the determining role in your soils pH.

  • Laurel Zito
    11 years ago

    I would not use vinegar at all because it is also used as weed killer. If you look up killing weeds on garden web using vinegar and hot water you will find posts so I would not use it on a plant you are not trying to kill.

  • gardengal48 (PNW Z8/9)
    11 years ago

    Actually, mixing vinegar in water is an excellent way of de-alkalining water in those areas - like SoCal - where tap or irrigation water tends to be overly alkaline. Growers of Japanese maples and hydrangeas in these areas typically use this recipe to water their acid loving plants.

    Vinegar is only effective as an herbicide if applied directly to foliage on a sunny day. Even that is not a particularly efficient method of killing weeds unless one uses the higher concentrated acetic acid. Otherwise, it has virtually no effect.

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