Will Weed And Feed Kill Hydrangeas? (Explained)

Blooming hydrangea

The idea of a 2-in-1 product that will simultaneously kill weeds and help your plants to grow at the same time sounds great doesn’t it?

But we all know that sometimes things that sound too good to be true actually are.

So will weed and feed kill hydrangeas?

There are a few things you need to know before you start applying weed and feed around your hydrangeas, or in fact, any plant.

So let’s get started.

Will Weed And Feed Kill Hydrangeas?

Certain types of weed and feed can be very dangerous when used around hydrangeas and could kill your plant. If you plan to use weed and feed pay close attention to the weed killer part of the product and avoid using any that contain broadleaf weed killer such as 2,4-D. Looking for a product tailored specifically for broadleaf plants is a less risky option.

It Depends on the Weed and Feed You Are Using

Weed and feed is a generic term for lawn care products that contain both weed killer and fertilizer.

So as weed and feed is an umbrella term, there is not a set list of ingredients for them, it varies from product to product.

To complicate the matter more, weed and feed is divided further as the weed killer part of weed and feed has two sub-categories:

  • Pre-emergent: Weed and feed with pre-emergent weed killer prevents weeds from even emerging. So you are treating the problem before it even exists so to speak.
  • Post-emergent: Weed and feed with post-emergent weed killer is used when weeds have already reared their ugly head and you want to get rid of them.

If you are using a weed and feed with a pre-emergent weed killer, its main ingredients will usually be something like 2, 4-D, dicamba and MCPP.

If you are using a weed and feed with a post-emergent weed killer, then expect to see Dithiopyr/Dimension on the ingredient list.

The fertilizer part will remain largely the same for both sub-categories, and contain varying levels of nitrogen, phosphorous, and potassium.

Now I will put it out there that, generally, I steer away from weed and feed products, but if you are planning on using one I would suggest you read the ingredients list very carefully.

Many weed and feed products contain 2, 4-D, which will kill any broadleaf plant including hydrangeas.

No matter how many precautions you take 2, 4-D can vaporize and drift to harm plants a considerable distance away from where it is being used. It can also be absorbed by roots.

So avoid any weed and feed product that contains 2, 4-D or any herbicide that contains a broadleaf weed killer.

What You Should Do If You Get Broadleaf Weed Killer on Your Plant

Water coming out of watering can

If you use weed and feed on your hydrangea and then realise it has a broadleaf weed killer in its ingredients you need to act as soon as possible.

The chemical will usually take around 24 hours to translocate to the roots, so after that you have most probably left it too late.

Hose it off immediately and thoroughly and then water, water, water! 

Give your plant around 1-gallon water per watering.

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If the plants are small enough you could try digging them up, washing the soil from their roots and then replanting them in a new spot, far away from their original location.

Remember also not to plant anything in any affected soil for a good amount of time when the residue has washed away, the label of the weed and feed should give details.

If You Are Going to Use Weed and Feed Make Sure Its Fertilizer is Balanced

As mentioned the fertilizer part of weed and feed will be made up of nitrogen, phosphorous, and potassium (NPK).

Hydrangeas generally prefer an all-purpose, balanced fertilizer that contains an equal amount of each substance.

So as well as checking the weed killer ingredients before using weed and feed, you also need to check the composition of the fertilizer.

Try to Avoid Granular Weed and Feed Products

Gary Fish, an environmental specialist at the Maine Board of Pesticide Control, has similar views to me when it comes to weed and feed products.

He has said they “are unnecessary and harmful to the environment” and believes they contain “20 to 30 times more pesticide than is needed.”

I think the problem is more acute with granular weed and feed products as they are designed to be applied to large areas, which almost contradicts their use.

That is because the weed killer part of the product is there to deal with problem spots of weeds, which usually only account for a small percentage of a garden, whereas the fertilizer part is meant for a bigger space.

But in short I don’t particularly like using weed and feed products around plants.

I would much rather buy a product specifically made for broadleaf plants and then apply it carefully on any offending weeds.

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Does Glyphosate Kill Hydrangeas?

If you purchase a weed and feed product that contains glyphosate, be very careful about how you use it.

Glyphosate is a nonselective weed killer that will kill most plants, including hydrangeas. It is found in many popular weed killers such as Roundup and Weedol.

If you accidentally spray a product containing glyphosate on your hydrangea, again you need to act quickly, in fact time is even more of the essence in this case.

You need to soak the hydrangea with water within 30 minutes of application and do everything you can to rinse off the product.

Saturate the leaves with water so it runs off them constantly, if this isn’t done immediately the chemical will already be working its way into the root system.

However, there is no guarantee of survival regardless of how much water is sprayed onto your plant and how prompt your action.

Can Bone Meal Be Used On Hydrangeas?

Bone meal is actually an excellent fertilizer to use on hydrangeas as it is a fantastic source of phosphorus.

Phosphorus helps establish good roots, which are vital for any plant to grow well. It should get your hydrangea off to a good start for summer growth and lead to large and bright blooms.

It is also a slow-release fertilizer, meaning it doesn’t stress plants by triggering a sudden growth.

If you are wondering how much bone meal to use on your hydrangeas, then generally you should add around 2 to 4 cups (1 to 2 pounds) around your shrubs. Instructions should be found on the product.

Sprinkle it around your hydrangea (and other perennials), rake it into the soil and then water thoroughly.

Even though bone meal is a truly organic fertilizer there is still the danger of using too much and damaging your plants.

So don’t be tempted to overdo it!

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Can Blood Fish And Bone Be Used On Hydrangea? 

Another extremely good and well-balanced fertilizer to use on your hydrangeas is blood fish and bone.

It has an NPK rating of 5-5-6, and promotes leafy growth early in the season.

You can’t really go too far wrong with either bone meal or blood fish and bone. Bone meal generally has a slightly higher level of phosphate and nitrogen in comparison to blood fish and bone.

Blood fish and bone is also a slow-release fertilizer, and it is very gentle so won’t burn the foliage or roots of your hydrangea.

As an added bonus it is also pretty cheap!

Simply scatter a handful around each plant and then work it gently into the soil.

Final Thoughts

My own personal preference is not to use weed and feed around my hydrangeas, as it is likely to do more harm than good.

If you are looking to get rid of weeds around your plants, then I would suggest buying a product made specifically for broadleaf plants.

Failing that, if you use weed and feed, look at its list of ingredients extremely carefully, in particular the make-up of the weed killer part of the product.

Two excellent alternatives in terms of fertilizers to use on your hydrangeas are bone meal and blood fish and bone.

They are truly organic and will get your plants off to a great start in the summer and should lead to healthy growth and vibrant blooms.

Good luck!

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