How do you get a giant sequoia to go dormant

ShadyStump

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Yeah, it does help to know where you are. If you click your icon at the top of the screen, and select 'Account details' it will open a page where you can add your location or USDA growing zone. You can be as specific or general as you like, but we really don't know what you're dealing with if we don't know where you are or have more details/pics of your tree.
 

Bonsai Nut

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Welcome to the site!

So much depends on where you live, and the conditions in which the tree is being kept. Think of giant sequoia like a large cedar or juniper. They tend to have a spring growth season, a summer pause, a fall growth season, and then a winter pause. If you are further north, they will have a more significant winter dormancy. But you can't "trigger" dormancy - at least not without a completely enclosed environment where you can adjust lighting cycles and temperature. Trees go into and come out of winter dormancy very slowly - over the period of months. It isn't as simple as, for example, putting a tree in a walk-in cooler for a couple of days.
 

rockm

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For the most part, you cannot force a tree to go dormant. It is a process of the accumlulation of a variety of things, particularly shortening day lengths between mid-summer and autumn. If you are keeping this tree indoors, it will die.
 

rockm

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I live in zone 6b will it get cold enough to go dormant
Cold plays a subordinate role in getting a plant to go dormant. Simply making it cold will mostly just kill off foliage. The dormancy process begins at the summer solstice when the days are longest. The shortening days (two minutes a day after the solstice) reduce the daylight exposure for trees. That shortening daylength triggers hormones in the tree that tell it to begin the process of converting from active spring growth to preparing itself for dormancy. At this point, it's not anything to worry about. It's still summer. You have a month or more of it. Let the tree alone. Hope you have a place for it to overwinter. 6b is a little on the cold side for sequoia
 

Forsoothe!

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Length of winter is as or more important than depth of cold. The ground is affected differently than the air and slowly changes temperature. Giant Sequoia (Sequoiadendron giganteum) is a zone 5 tree in the far west, but falls into the category of "not certainly hardy" in mid-western zone 5 where the occasional Alberta Clipper will linger for a couple weeks and kill the roots. This is not a new tree. There are almost none that have survived in the east because our winters are longer and colder, -look around. Protect the roots from freezing and you're golden.
 

WNC Bonsai

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Don’t start messing with the roots and repotting it into a bonsai pot until you learn more about bonsai culture and how to care for this particular plant. Otherwise you’ll be back here asking us how to save it and then why it died!
 

Mikecheck123

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Length of winter is as or more important than depth of cold. The ground is affected differently than the air and slowly changes temperature. Giant Sequoia (Sequoiadendron giganteum) is a zone 5 tree in the far west, but falls into the category of "not certainly hardy" in mid-western zone 5 where the occasional Alberta Clipper will linger for a couple weeks and kill the roots. This is not a new tree. There are almost none that have survived in the east because our winters are longer and colder, -look around. Protect the roots from freezing and you're golden.
There's a 150 year old giant sequoia in Michigan. But it's a real oddball.
 

rockm

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Someone said this tree is hardy to zone 5. It's not, unless you have a specific colder-hardy variety named "Hazel Smith" (no its not a joke--specific cultivars or varieties of plants with specialized growth are often named for their discoverers or discoverer's relatives, etc.)

Additionally, the main variety of giant sequoia is hardy to Zone 6. Typically in bonsai practice, you subtract a hardiness zone for trees used. That's because in a container, they are more vulnerable to temperatures and can't rely on the ground to insulate their roots. That means your Zone 6 tree is really bonsai-hardy to Zone 7.

Unless you have somewhere to overwinter this tree that stays relatively and RELIABLY warm--like upper 20's, or better yet, 33-35 degrees all winter, you're not going to have much success.
 

LittleDingus

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I'm in zone 6a. This sequoia along with several others was a nursery plug a little smaller than the OPs 3 winters ago.

20210803_135927.jpg 20210803_135945.jpg

It is kept outside year around except when daytime temps stay below freezing or we're expecting an ice storm. It has been buried in snow...but ice can be more destructive. This past winter it was in the garage for about 2 weeks in February when we had sub zero daytime temps. It was outside the rest of winter. It did lose 3 major branches to die back this winter, though. But, as you can see, it's pretty vigorous at the moment. Not as vigorous as it was last summer...but I also repotted it in early spring so it needed to re-establish some roots.

The trick is that they are pretty susceptible to dehydration. They can handle high heat and some drought but their roots should remain moist...or at least not shriveled...to avoid dieback. I water at least once a week in the winter. Usually I'll poke my finger as deep into the soil as I can and make sure its evenly moist. If it is, I wait a few days and check again.

Frozen roots cannot absorb water. Dry windy winter air can then dehydrate the foliage pretty quick even with the temps low. I place mine where there is a bit of a wind block but still lots of sun. I'm still on the fence about whether they really need sun at those temps...but it does make it less likely I'll burn it in the spring. I give my poor saguaro sunburn moving it back outside just about every spring :( I don't worry too much about night time temps as low as 20F as long as the day temps get back above freezing. If daytime temps are below freezing for more than a day or two, I move them into the garage to allow the root ball to thaw enough to be able to absorb moisture.

I have also kept ones the size of the OPs tree inside for the winter in a bright window without apparent ill effects. I've found these pretty trivial to start from seed and have started batches of seed in October to move outside the following summer without issue.

I have a couple of cultivars.

20210803_140301.jpg

The top left is a from seed "normie". Top right is a "french beauty": new growth is often white until chlorophyll fills in. Our spring was too cool and it didn't do that this year :( Bottom is a "pendulum"...it was very lush last year but had a lot of die back of the lower branches this winter :( They froze solid this winter even in the garage because we had sub 0F temps for nearly a week straight. I think that stressed them significantly...then we had a cool rainy spring which held them back further.

From my experience, it is certainly possible to grow sequoia in zone 6b. You do need to understand when and how to take special care to get them through the rough spots ;) For me, that's as simple as occasionally moving them into the garage...and having the neighbors stare while I water trees in the middle of winter ;)

Keeping them "small"?? This is the only one I've tried keeping "small" so far:

20210701_154611.jpg

The rest I'm still trying to make "big". It was freshly germinated in a window last November and wintered entirely indoors. They were moved outside in early spring. I had planted all 3 redwood species for the "forest from seed challenge".


Surprisingly, all the dawn redwoods died off from that planting so all I have in that pot right now are coastals and sequoias.

20210701_151715.jpg

All 3 germinate readily from seed if sown properly. I almost always start a batch of dawn redwoods in the fall to have something fun to watch grow while it's grey and gross outside. The first growing season is long...but they deal if treated properly.

If you want a "bonsai" in the sense of a judged competition tree that is perfectly manicured and inspires awe amongst this forum, this is probably not the right species :( If you want a "bonsai" in the sense of a tree in a pot that us common folk will think is pretty cool and unique, my opinion is that it is perfectly doable :D
 

rockm

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You can get a "competition tree" with the species. This one has been around quite a while:

 

LittleDingus

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You can get a "competition tree" with the species. This one has been around quite a while:


Grown in 6b where the climate is on the edge of what's optimal? You, yourself claim hardiness in a bonsai pot is more like zone 7.

The weather we had in February here would have killed mine without intervention...no question about it. Even with intervention, I lost a lot of structural growth to year. I don't care at the stage my trees are in...but making a show quality tree when your structure can change yearly due to your winters is tough.

But again, if all you want is a pretty enough tree in a pot. It is doable without extraordinary effort.
 

LittleDingus

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I'm not trying to dispute you @rockm...just stating my experience.

For reference:

Here was that same tree coming out of winter. Most of this occurred after our deep cold spell.

20210627_104147.jpg 20210627_104203.jpg

One side of the tree died back pretty hard.

Here it is after some cleanup...I left a lot of dead foliage because there was some live budding in there.

20210627_105849.jpg

This year has been my worst for die back on these by far...but this kind of die back has occurred after every winter.

Now, you can say this was all my fault and I don't know how to care for a tree. That may be a fair statement, actually :D But I am not inexperienced despite my fake internet point tally and short membership on this forum. While it is possible to keep these trees alive in 6b in a pot...they are, shall we say, on the high maintenance side in this zone...at least compared to my dawn redwoods which I've done just about everything one can do to kill a tree and they trooper right on through!
 

rockm

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I'm not trying to dispute you @rockm...just stating my experience.

For reference:

Here was that same tree coming out of winter. Most of this occurred after our deep cold spell.

View attachment 389772 View attachment 389773

One side of the tree died back pretty hard.

Here it is after some cleanup...I left a lot of dead foliage because there was some live budding in there.

View attachment 389774

This year has been my worst for die back on these by far...but this kind of die back has occurred after every winter.

Now, you can say this was all my fault and I don't know how to care for a tree. That may be a fair statement, actually :D But I am not inexperienced despite my fake internet point tally and short membership on this forum. While it is possible to keep these trees alive in 6b in a pot...they are, shall we say, on the high maintenance side in this zone...at least compared to my dawn redwoods which I've done just about everything one can do to kill a tree and they trooper right on through!
I said it is possible IF you can properly overwinter it. I'd bet most people aren't going to take the time. Marginal species like this require attention in the winter that can tire you out. I have a live oak collected in Texas here in Va. Have had it for over 25 years now. The species is marginallly hardy here IN THE GROUND. It was in decline after a few winters in mulch in my backyard. Didn't die outright, but was losing steam. I have taken it to a cold greenhouse for winter storage for 20 years now without fail. It has prospered with that treatment. It has taken commitment and caash (not to mention elbow grease since I have to heft the 120 lb tree to the street and get it loaded into a special purpose built box in the back of the pickup)The trip to the nursery is two hours one way on I-95 (busiest most congested Interstate in the U.S.) and costs not an insubstantial amount of money to store there. You are at the beginning of your journey with these trees, so before you start telling me I'm wrong, let's see if you still have them 25 years from now. BTW that die back is telling you something about the future...
 

Forsoothe!

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There's a 150 year old giant sequoia in Michigan. But it's a real oddball.
Yeah, it has its feet in Lake Michigan. It is within some pretty close distance to the shoreline, so the roots don't freeze.
 
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