Pieris Turning Yellow

Farmington, UT(Zone 6b)

My Pieris japonica 'Mountain Fire' has gone from a healthy green and red to a distinct yellow (on the outer leaves--the ones on the inside of the shrub are still green). What could be happening? It's getting regular water through sprinklers, is in full sun, and has had no supplemental fertilizer (just compost in the hole when I planted it in April-ish). Could it be the heat/sun? It's been 90-100 degrees here regularly lately. Oh, and the brown spots on the leaves almost look like burn marks, making me again wonder if it's the heat/sun. What can I do?

Thumbnail by GardeningMommy
Ayrshire Scotland, United Kingdom

Hi Gardeningmummy, your plant sure looks stressed by sun/heat, the first signs are the outer leaves turn yellow and then brown, it is a good idea to stick your finger into the planting hole and see if under soil is dry, if so, you need to soak the roots, also I could be wrong, but I thought pieris liked a kind of acidic soil, well mine do anyway, the best thing to do is to add an empty plastic juice carton with the bottom cut off and the narrow neck stuck well into the soil, as close to the roots as poss, then water into the carton so the roots are getting s good drink, or move the plant and this time, add some manure/leafmoul to the compost in the hole to help retain moisture, the new growth should be red and turn green later as the leaves mature, so maybe cut off the dead leaves to give it a chance to make new growth before the end of season, sometimes in the heat, a crust forms on the top soil and prevents water penitrating to the roots where it is really needed.
Good luck, Weenel.

Dublin, CA(Zone 9a)

WeeNel is right, they do like acidic soil better, but I don't think that's the primary problem here. I think in a hot summer climate like yours, they will probably need to be in shade during the hottest part of the day. I can't really tell from your pic how much shade it would get in the area it's in, but it looks like a pretty sunny area. It doesn't really look like a watering issue with me, looks more like too much heat/sun. Could be it's not getting quite enough water either, but just watering it more isn't going to fix the problem, I think the plant probably needs to be moved to a different location.

Windsor, ON(Zone 6a)

I agree with ecrane. Needs some shade. (or a good spf sunscreen LOL) I'd be moving that puppy if I were you. Make sure that you use a good transplant/rootstarter fertilizer to help get the roots established before fall.

Farmington, UT(Zone 6b)

Thank you all for your replies. Looks like I've got to do something if I want to save this nice little shrub! My garden is brand new, with no trees yet, so unless it's against my house (and this one isn't), just about everything in my yard gets very full sun. Basically, this Pieris doesn't get a bit of shade all day. So much for 'full sun' on the tag, huh?

I think I'll move it into the part-sun area on the north of my house. It gets sun till about 2 or 3 in the afternoon. Will that do, or would that just be moving it from too much sun to too little? Will the plant benefit from peat moss (that's what you use for acidity, right?) mixed in with the compost that I have been adding when planting a new plant?

As for rootstarter, I know I have some kind of Miracle Grow (I think) root stimulating hormone stashed away somewhere, which I've used for encouraging rooting on houseplant cuttings. Can I use that on this Pieris, or do I need to head to the local garden center to get something else?

Again, thank you all!

Mays Landing, NJ(Zone 7a)

I agree with everyone above, in the mean time you might want to feed it some iron.

Dublin, CA(Zone 9a)

A lot of people swear by Super Thrive for transplants, I'm not familiar with the Miracle Grow stuff, if it's a rooting hormone that you dip cuttings in then I don't think people typically use those for transplants, but if it's vitamins and stuff like Super Thrive then it may do the same thing that the S.T. would.

The area getting sun until 2-3 definitely won't be too little sun, I would worry that depending on how hot your summers are, it might still be a little too much. I think your summers are probably hotter than mine, and I had one at my old house where it got dappled shade during the morning, then bright shade all afternoon and it did just fine. But at least it'll be in shade during the hottest part of the day, and the north side should be slightly cooler so it should do better over there.

Ogden, UT

I live here in Utah also, and it sure has been hot this summer! The picture of your mountain pieris looks identical to mine. I didn't realize how yellow it had turned until I looked at the same plant in the nursery a while ago.

Mine is planted in full sun, in fact I don 't think it receives any shade at all.
Think I know the perfect spot for it where it will be happier.
Thanks for info

Farmington, UT(Zone 6b)

Flowerprincess, is your Pieris new to your yard too, or is it an established shrub? This plant is supposed to be able to take full sun, so I'm wondering if mine is yellowing in response to the heat (yeah, it sure has been a hot one this year!) largely because it's still setting down it's roots. Does anyone have any ideas on this? Could I erect a little shade canopy over the shrub to help it through this summer, or is moving it pretty much my only solution?

Dublin, CA(Zone 9a)

If you look up Pieris in Plant Files, it lists a range of acceptable sun exposure all the way from full sun to part shade, I think a couple entries even list full shade as being OK. Anytime I see a plant that's listed as liking sun or shade, I always assume in a hot summer climate it's going to be happier with afternoon shade at least. Even some plants that are listed strictly as full sun will be happier in hot climates with some shade during the hottest part of the day.

I don't live in your climate though so it's hard to say for sure whether your plants are just still getting established and that's why the sun/heat is stressing them or whether they really in the long term need to be moved (this is my guess though). Do you have neighbors or friends who live near you who are successfully growing these in full sun? If you do, then it could just need to get established a little better. They'll certainly do fine if you move them to a shadier location, so if in doubt that's what I would do. It would be better though if you could find a way to shield it from the sun for the summer and then transplant during a cooler time of the year, the middle of summer is not a good time to transplant things. So if you can do the shade canopy for now that would be the best solution

Ogden, UT

GardeningMommy, it should be pretty established I planted it last year late spring, I actually planted 2 and lost one. Even though it has been hot, my spirea bushes and other plants are all doing great, but pieris is stuggling. I wonder if it doesn't like the soil. I have clay but I amended the soil with compost.

I use a product made by fertilome, called 'root stimulator'. I bought it at a local nursery and use if for all my trees and shrubs.
I definatley decided this year after this heat, I need some serious shade, I am a hosta lover and need some shade, I planted 3 trees this year, but need to get some more!

Farmington, UT(Zone 6b)

ecrane, thanks again for all of your advice. I don't know anyone at all who's grown this shrub, so who knows how it fares in out hot, dry summers in full sun, even when mature. I'll shade it for now and then just plan on moving it in the fall, as I am in a new neighborhood, and we have no trees (over 3 feet tall) around. I'll just have to rely on the shade of my house! Hopefully I won't run into tons more problems like this in my backyard, as I have about 1500 sq. feet of flower beds in basically this same light. Everything back there is new, but I seem to be having good luck with achillea, aster, chrysanthemum, campsis, liatris, anthemis, gaillardia, festuca, glads, sunflowers (duh), kniphofia, dahlia, phlox, campanula, cerasitum, papaver, and some others. We'll see how my garden grows over time!

Dublin, CA(Zone 9a)

I think you'll have good luck with most of your other plants, the ones that I'm familiar with should be fine with full sun and heat.

The one thing to watch out for if you put the Pieris near your house--they tend to like acidic soil, and if you have a concrete foundation it'll tend to raise the pH of the soil in the bed right next to the house, so you may want to add some peat or something to lower the pH from time to time.

Farmington, UT(Zone 6b)

Thanks for the tip. I had no idea concrete changed the soil at all. I'll be sure to mix some peat moss in when I transpant it. When you say "from time to time", what do you mean? Can I put peat moss as a mulch for a plant that likes acidity? I have a peegee hydrangea that I hear likes acidic soil as well, but I didn't add any when I planted it. Can I top dress it and all of my other acid lovers?

Dublin, CA(Zone 9a)

The frequency is going to depend on a lot of factors such as what the original pH of your soil is, what the pH of the water is that you are watering your garden with, etc. All I really meant by that is you'll probably have to repeat the addition of peat more than once since your soil's pH will always have a tendency to go back to what it used to be over time. You're not going to be doing it every week or anything, I would guess a couple times a year at most. And there are other things you can buy to drop the pH too, wouldn't necessarily have to use peat. I'd definitely check what your soil pH is now before you do anything though, could be your soil's already fairly acidic and then there's no need to do anything.

I wouldn't use peat as a mulch, when it dries out it is VERY hard to re-wet, so if you use it as a mulch and it dries out, then you have a layer of stuff over the top of the soil that doesn't want to let water through. Not a good thing! So I'd work it into the top several inches of soil instead and use pine needles or bark chips as mulch (Pine needles can help improve the acidity of the soil if you can find those, they're more readily available in some parts of the country than others)

Sydney, Australia

Aged cow manure is ideal as a good gentle mulch for acid loving plants and the worms will take it down for you.....Pieris will tolerate a lot of sun but in harsh temps it prefers some shelter....most plants like this one like morning sun and afternoon shelter. :)

Ayrshire Scotland, United Kingdom

the probs with the pieris is that we grow them for the red/yellow or orange coloured foliage rather than the little white flowers that a lot of folks dont even see, so the coloured tips that we want, are the new growth, so these are very tender and the hot sun just fries then, if not shaded, the rest of the plant starts to go into shock and weeken, then die off sets in, they are tough plants once established, but that will take a couple of years, mine is in full sun hear in UK, but that is in temps of about 65 to 70 at the hottest, your talking much hotter than that, your other plants are more classed as arid plants and will be able to take more heat than your pieris, these plants come from the same regions as Azalias and Rododendrons therefore cant take the prolonged heat and dry soil, you should either move it into a more shaded area till it settles a bit, once you have your shade tree/plants better established, you can them move your pieris back to the site you have it when shade is avaliable, I would'nt fertilise it just yet till it comes out of it's stressed state, then give it some acidic plant food, the best way to help your soil for this type of shrub, is to add lots of leaf mould into the soil/hole at planting time and give a good water, the leafmould will help the acidity and also help retain some moisture you can also buy acid compost. these plants just need the right soil type and shaded area to get established, maybe you have just chosen the wrong plant for your area and conditions, but good luck, look after the acidity and water it should pick up a bit. WeeNel.

Orange, CA

GardeningMommy: Can't help but notice your bare ground around the plant. You may want to seriously consider a layer of mulch 2-3 inches deep in order to keep the roots cool. I prefer using composted material, as wood chips tend to use nitrogen from the soil as they decompose, where compost will add nutrition. Around acid loving plants you could even mulch with acid planting mix for azaleas. Just keep it away from the crown of the plant so that you don't rot the crown. It will feed the soil as it decomposes so that the soil can feed the plant. Just replace it as it gets low, maybe 2 or 3 times a year at the most.

In addition, shrubs and trees really need a good deep soaking in order for the roots to grow deep into the soil, rather than at the immediate surface. If you have the chance, especially the first year, soak your new trees and shrubs once or twice a month in the warmer months (maybe once every 6 weeks in cooler weather, if you do not have adequate rain) with a slow hose or soaker hose until the ground becomes wet at least a foot down. The only way to tell is to dig down and see how wet it is. Once you establish a watering pattern, you will be able to tell what is working for you.

Finally, do not feed a struggling plant. Fertiliser will further stress the plant. Superthrive or a vitamin hormone would be a good idea, be sure to use as directed and flood the root ball so that it goes deep down to the root.

Hope this helps, there is so much to learn.

Ogden, UT

K, I researched this awesome plant; interesting. Mixed information, some said full sun, some said full to partial, one said shade lover, all I know is after looking at what this plant should look like, yep its distressed allright!
So even though it's been hot here in the day, I decided my mountain fire pieris wasn't going to make it if I didn't move it. The leaves are getting brown on the edges with spots,there has been absolutely no growth whatsoever this whole year, so I dug it up and planted it at 9:00 p.m., ha ha I'm a night time gardener, only time its nice and cool!

I used a soil mixture with compost, going to add some peat, and moved it to a shady spot with afternoon sun, and watered it with some good root starter not fertilizer.

I'll let you know how it does....

This message was edited Jul 23, 2007 9:57 PM

Ogden, UT

Here is a picture of what it should look like.....

Thumbnail by flowerprincess
Farmington, UT(Zone 6b)

FP, isn't it pathetic how mine (and I'm sure yours) looks after seeing the picture of what this Pieris is supposed to look like? Sheesh! Anyway, maybe I'll follow your lead and move it despite the hot weather. It's only getting worse, so who knows if it will make it till fall. I know it's supposed to be cooler in the next few days, so maybe I'll try it then.

Gardenerme, thanks for the tips. I really want to put a mulch down in my yard, but I've allotted about 3000 sq. feet of garden space, and to mulch that with bark chips would cost about $700! So I have just held off entirely. We have them in the front of the house, which helps tremendously with moisture and weeds, but doing the backyard is just a bit too much for now. I have mulched weedy areas with grass clippings. It's ugly, but worked. Should I think about doing that in my flower beds?

This message was edited Jul 24, 2007 9:42 AM

Alamogordo, NM(Zone 7b)

If that was in my yard I would water deeply adding some Green Light Iron and Soil acidifier, or whatever brand you can find. If you have alkaline water in your area I would also scratch some sulfur into the soil around the plant--it is cheap and comes in small bags. Then add a layer of mulch. I think that moving a stressed plant in the heat of summer will usually kill it. You could also use shade cloth or even just a lawn chair to give it some relief form the sun until it gets established.

Ayrshire Scotland, United Kingdom

The picture that Flowerprincess has posted is a mature Pieris that has been given the proper care and soil conditions, it will take several years for the plant to reach that stage of maturity, the plant in question, is still a very young plant (like a baby) therefore it needs cooler conditions, acidic soil and watered at its roots under the soil for it to stand any chance of survival in the extreme heat you are discribing, these are mountain plants that originate at the edge of forest regions in the same conditions as for Azalias/Rododendrons and Camilias etc, so we sometimes try to grow things in conditions that the plants wont be happy, I think all our comments are telling us that the Pieris is suffering from over hot soil, too much sun on the tender foliage as it is a young plant and really generaly the wrong growing conditions, there are also several different types of Pieris, some of which will take a bit more sun than others, but the Mountain Fire really cant take these conditions till well matured and established.
Good luck. WeeNel.

Ogden, UT

I forget sometimes it takes a plant time, gardening is trying to teach me patience... lol
I always look at other people's yards and think why doesn't mine look like that, than have to remember their gardens are much more established, my hostas have been in for one year, compared to someones who have had theres for 5 or more! ha ha

I purchased some Iron soil acidifier this weekend and also placed mulch around it, hopefully i can create better conditions for this plant. We have had some rain and cooler weather the last week or too, it seems to be doing better already just having some shade.

This message was edited Jul 29, 2007 8:51 AM

Ayrshire Scotland, United Kingdom

Your doing well, when you see other more mature garden, you like the plant so you go get them and enjoy, our gardens grow with us remember, plus it is so much easier to look after a small specimin plant you know will grow well, especially in hot weather, than to buy a huge expencive full grown plant that you will loose sleep over if it started to go yellow/brown or die on you, small is best and you have the pleasure of watching it grow along with your gardening experience, so good luck, enjoy your gardening and have fun. Weenel.

Ogden, UT

Good new, my pieris has really greened up, new foliage and I am getting the flowers on it! Must be happier in the shade :)

Farmington, UT(Zone 6b)

YAY! Flowerprincess, I'm so glad to hear it! As for me, I decided to wait until it cooled down a bit so I didn't kill it from shock. But looks like I didn't need to wait! Oh well. I'll be moving it soon, and I can only hope that it will be as happy with the move as yours is! :o)

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