Dawn Redwood foliage problem.

[Bonsai Buddy]

Hi all! Just a quick question. As you can see from the photos some of the foliage on my dawn redwood is turning reddish brown. Could it be too much fertilizer? I hope that it’s not something worse. I fed it with an 18-4-10 slow release fert in teabags for about a month and a half, and then switched to a 12-10-11 slow release fert that’s urea free and supposedly more gentle and much longer lasting. But this leaf browning has been getting worse the past few weeks. So I took the fert bags off a few days ago. I water my redwood once a day or once every other day depending on the weather because I know they like wetter conditions and because he has well draining soil. What do you guys think is going on? Was I right to remove the fert teabags? I don’t think this could be caused by sun because I have him under a shade netting most of the time. Please share your insights, and thanks for your time.

 

[Bonsai Buddy]

This thread went unanswered awhile back. I still have not put the fertilizer teabags back on. I just gave it one or two waterings with a mild liquid fert since I asked my question above. The problem has not necessarily gotten any better or worse except I pruned it a bit which made the effect not as noticeable. It’s a deciduous tree so I guess the red burned leaves will fall in due time. Although I have other deciduous bonsais that didn’t lose all their leaves last year. I’m in zone 10a so maybe it does not get cold enough for a full self defoliation. If anyone has any input I would be happy to hear it, thanks much.

 

[Mapleminx]

I don’t have as much experience with this species as others on the forum but I don’t want you to feel ignored.

Is there a chance it is too wet? I know they like to be on the wetter side but is it possible it’s not drying out much between waterings?

 

[Deep Sea Diver]

This thread went unanswered awhile back. I still have not put the fertilizer teabags back on. I just gave it one or two waterings with a mild liquid fert since I asked my question above. The problem has not necessarily gotten any better or worse except I pruned it a bit which made the effect not as noticeable. It’s a deciduous tree so I guess the red burned leaves will fall in due time. Although I have other deciduous bonsais that didn’t lose all their leaves last year. I’m in zone 10a so maybe it does not get cold enough for a full self defoliation. If anyone has any input I would be happy to hear it, thanks much.

Your Dawn looks pretty healthy to me. My Dawn has a bit thinner needles and during hot spells the tips of certain needles look crispy. Since the vast majority of the needles are healthy as can be, I’ve been chalking it up to some needles are weaker then others.

When I looked closer to photos, I seems you are being affected on top and that area is somewhat yellowing. The yellow may be young growth, but that growth is also being affected… see brownish areas on those needles… . That would jibe the sun damage hypothesis.

Things you can do, cut down on the sun and mist frequently. Redwoods get water through their needles as well as their roots.

cheers
DSD sends

 

[Bonsai Buddy]

Hi @Mapleminx and @Deep Sea Diver Thanks for your replies! Sorry I was a little long in getting back to you. @Mapleminx My soil is quite well draining, Just a mixture of high fired clay particles and fine pine bark. Plus it has been getting rather hot here lately so I don't think I'm overwatering necessarily now. But when I made my first post it was not too hot so I possibly could have been overwatering a bit then and that was when the problem showed itself. @Deep Sea Diver Thanks for saying my Dawn looked healthy. I got it as a gift around Christmas last year and since it is deciduous it was just a stick lol! Not too many branches but a good amount of buds. So it has been fun watching it this growing season. Honestly I don't think I've misted him for several months. I got fungus on my Chinese sweet plum by doing that excessively so a bit scared to get back into it. But I suppose if I do it early enough in the day it might not be so bad. Also I have him under a 50% sun block garden netting around the clock, so you wouldn't think it would be getting too much sun... But you are right the top is browning and I have seen him perspiring through the needles so maybe I should put him under my awning sometimes. Thanks again to both of you for replying, this is my first Dawn Redwood so I tried to use knowledge from my favorite bonsai book but everyones climate is different so I'll make some modifications. Have a great night guys.

 

[Deep Sea Diver]

Under the Awning would be a good thing to do. Also you might consider keeping your trees out of the wind if they are not so located. btw overwatering would affect the entire tree vs the top.

Redwoods are pretty tough and can handle the misting…. (As you hinted, It helps to mist so the foliage is dry by dark) sunburn, that’s a whole other story which can kick off a cascade of nasty events.

….I noticed your maple and conifer appear to also be affected….

cheers
DSD sends

 

[Dzhokar]

I'm going on the second year with my dawn redwood, so definitely no expert. But I can tell you what my experience has been.
As background info, I'm in zone 8a around the Dallas area. So it gets pretty hot and is fairly dry. I can only water once a day.
The first year I had this tree I had the same problem you do. The foliage crisped up and I was worrying about it a bit. So I put the pot in a tray of water about 2 inches deep.
Since then it's been thriving. The leaves are healthy, no browning. It uses about half of the water in the tray each day.
Roots are growing into the water and stay looking healthy. I think these trees can grow with their roots fully submerged but not entirely sure about that.

*edit* Forgot to mention that I have it partially shaded under a stand of banana trees.

 

[Deep Sea Diver]

Interesting !

I always thought Dawn Redwoods were tough and could take a lot of water.

Lots of q’s here.

How tall/age is the tree?

What type of media do you have this tree in?

Do you also water?

When do you decide to taper on/off this regime?

Have you looked at the roots and soil on the bottom of the pot?

Like to see how this works for a couple years.

Cheers
DSD sends

 

[Forsoothe!]

I don't think DR is a 10a plant. Southern California is too general of a term to describe a location for plants, too. The edges of leaves, the youngest and oldest leaves, those that are presented to the sun at the most direct angle, etc., are the first to be shortchanged when the moisture level in the pot along with elevated temperatures, mid-day sun and stronger winds combine to stress the tree. Gift bonsai are never appropriate because, like a gift pet, it requires attention and conditions that may or may not be available. If OP wants to continue bonsai, then a Bougainvillea or Fig should replace the DR. I seriously doubt it will survive past a year or so. It needs a rest period that is not available in zone 10a.

 

[Deep Sea Diver]

@Forsoothe! is totally correct Dawn Redwoods are consistently listed as being in USDA Hardiness zones 4 - 8. Arrgh. That's basic and it didn't even come to mind!

Its interesting to see you both are managing with the trees as is at this point. However as Forsoothe so aptly pointed out that the trees do need a dormancy period. More important these trees also need a higher Day / Night temperature differential (see Michael Hagedorn's book Bonsai Heresy f for info on that topic.). But don't let that stop you trying to see how your trees react over time.

I really like the suggestion to get Bougainvillea. Since I'm in zone 8b that would be really edgy and a lot of work for me. We actually keep a big one in the Museum tucked into the greenhouse during at least half of the year. It would be great to see as I love to see a good bloom!

Cheers
DSD sends

 

[Dzhokar]

DSD,
I bought this tree mail order from Brussel's Bonsai. They listed it as 5 yrs old at the time so it's going on 7 yrs.
The base of the trunk was about 1" when I got it and is now approaching 2".
It's about 28 in tall, but I'll probably chop it to 18 ish late winter.
It's in Brussels nursery mix. Looks like about 40% peat and the rest grit (looks like pumice).
I do water it daily including the foliage and fill the water tray.
Watered about once a month in winter same as my other outdoor trees. Then put it back in the tray early spring.
Ummm think I let the tray dry early winter and then removed it... like Decemberish
It did go into dormancy last winter in 8a and budded out strongly early March.
I have not taken the tree out of the pot to look at the roots but plan to next spring to see how things are going. Water is not pooling at the top so not root bound.

Hope it keeps living because I like it!

I had some seedlings last year that I potted into 100% grit (pumice, lava, diatomaceous earth, expanded shale) without a water tray and they died in mid summer.

Hope that answers your questions.

 

[Bonsai Buddy]

@Dzhokar Thanks for the great advice about putting it in a pan of water! Dawn redwood are quite amazing to be able to tolerate that and thrive no less. I’ll have to give it a shot.

@Deep Sea Diver I’ve been misting my redwood everyday, sometimes twice if it’s early enough and I see the first mist has been fully dissipated and absorbed. Plus I’ve kept it covered more, and it seems to be improving a bit.

@Forsoothe! Thank you, I do realize Dawn redwood is not in my zone. But I have come to know that hardiness zones are not a definitive rule of the hobby. You can pretty much grow anything anywhere with the right resources and facilities. I have been growing out of zone trees for a long time with decent success both evergreen and deciduous. I have close to 30 bonsai and pre bonsai at the moment and most of them are healthy. I appreciate the suggestion of getting a fig those are pretty neat! Unfortunately I don’t recall any of my local nurseries carrying them. I’ll have to look harder. I’m not so keen on Bougainvilleas but thanks for the recommendation.

Thank you to everyone for the assistance!

 

[Esolin]

If most of the growth is remaining healthy, I wouldn't worry. I have a Montezuma Cypress, and while not the same species, is also a deciduous conifer, and over the past few weeks has started shedding interior growth like crazy. Nothing in my watering/fert routine has changed, but I think that heatwave we had a few weeks back triggered the leaf shedding response to reserve moisture and maximize effiency, as it's still pushing healthy tip growth. My plum tree has also been steadily thinning its leaves, I suspect due to heat stress/water managment. Same with my cotoneasters. I think many deciduous species can grow here, but they don't appreciate our baking dry summers and respond accordingly.

The other possibility is fungal issues if the roots have been too damp/hot. You could give it a dose of something if you suspect this is the cause instead of heat stress.