Growing giant sequoia in colder climates - Myths and Tips

1. Giant sequoias are easy to grow in Zones 5-9. 
   

   Growing sequoias in Zone 5 is challenging, particularly in 5A, becomes more feasible in Zone 6, and is considerably easier in zones above 6.

   Zone 5 is (mostly) a myth. In case you live in the southern most part of Zone 5B, then yes, it may be considered plausible but far from being "easy". If you live deep in Zone 5A then it is very to extremely difficult to keep them alive past 4-5 years mark. Zone 6 is challenging but there are many great examples where they do survive. Above 6 is not much of a challenge, consider yourself incredibly lucky and plant a sequoia as soon as practically possible. There is not much sense discussing Zone 4 and below.
   
   

   

   Europe plant hardiness zones 

   
   

   

   USDA Zones 2023
   
2. Growing sequoias is fun and unique experience.
   

   100% true.

   They germinate easily, you can see their progress readily in the first few weeks after germination, they look like pretty, miniature adult trees in the first two years. They have gorgeous blue-green foliage. 
   
   
   
   
   
3. Sequoias grow slowly over hundreds of years.
   

   Sequoias can grow rapidly with sufficient sun and nutrients, making it hard to protect them from extreme cold in colder climates, and indoor growth can lead to size challenges when transplanting.

   Myth about slow growth. They grow 2-3 feet per year and sometimes more with adequate sun and nutrients. In fact, it's one of their downfalls when grown in a colder climate. They grow so much in the first few years during summers that it becomes extremely difficult to protect them during typical Zone 5 freeze with -25F for a few days. You may get lucky a few winters in a row but then one week you will get -40-50F windchill and that's it. If you grow them indoors for the first few years they may and DO get very large, presenting a laborious challenge with planting them in a permanent spot. 
   

   

   Moving three year old sequoia to a permanent spot.

   
   
4. Sequoia seeds require stratification.
   

   Germinating sequoia seeds is relatively inexpensive and straightforward, with better overall success rates achieved by avoiding stratification and keeping seeds out of bright sun during germination.

   Mostly a myth. For those who aspire to grow sequoias at home from seeds, the very first step of germination is by far the cheapest. Sequoia seeds are cheap. They used to be even cheaper when JL Hudson were selling them by ounce, but still, you can get packets of 50 seeds for $3 in USA. For $30 you will get 500 seeds and without any stratification you will get way more live little trees than you would know what to do with. So a "pro tip" - don't bother with stratification. Get a few more seeds and start germination on coffee filters/paper towels. What is more important is keeping them out of bright sun during germination as documented in this excellent study below. Note, without any stratification about a third of the seeds germinated in George's experiment, which tracks well with my 12 years of experience.
   
   

   

   Source: George Maier GS investigation
   
   

5. Sequoias require a lot of space and sun.
   

   While sequoias eventually need ample space and sunlight, early moderate shade and protection from northern exposure, allowing slower initial growth, can enhance their survival and root development, improving resilience against winter damage.

   This one is a bit tricky. In general yes, eventually they will require both of these. But your issue more likely than not is going to be finding a secluded space protected from the north by other trees, big hills or both. The slower sequoias grow in the first few years, the better. What would you prefer, a 4 foot alive sequoia in 5 years or a 7 ft dead one after 3 years? So a moderate shade to limit growth is a plus. Also, if you travel to one of the national parks where they grow, you will find hundreds of little sequoia seedlings growing happily in the shadow of bigger trees. Growing over several summers without becoming too big allows the trees establish a root system, increasing the chances of a tree bouncing back after the top is lost due to winter damage.
   

   

   Dead 10ft tall sequoia from Jimhardy story on growing a giant sequoia in Zone 5

   
   
6. Giant sequoias are immune to diseases and insect predation.
   

   The claim that giant sequoias are immune to diseases and insect predation is a myth; they are particularly susceptible to fungal infections in colder climates, which can rapidly kill the trees, and require regular treatment with fungicides like Daconil for successful growth.

   No, really, I read it on some sites stating that sequoias survived for thousands of years by being resistant to diseases. It's a 100% myth on diseases and though not often but you do get some bugs making home on your baby sequoias. Fungi are sequoia nemesis in colder climates. They kill them and kill them fast. Most times by the time you notice dreaded streaks of black/brown/light yellow the tree is all but dead. Some fungus is black starting from tips and traveling inward the tree eventually overtaking them entirely. More often it starts from inside the tree and travels in brown/yellow streaks towards the tips. Only by applying a strong fungicide REGULARLY you will get even a remote chance of growing a giant sequoia in Zone 5. I recommend Daconil (Chlorothalonil). Even with regular Daconil application you do see occasional fungus damage on older foliage and branches closer to the trunk but with quick reaction and removal you can keep your trees alive. I have not seen signs of fungus on sequoias in California but in Iowa it's a plague for sure.
   
   That's what one particular strain of fungus on GS looks like:
   
   
   
   

   Look closer. You will see brown spots on the branches and needles. After a few hours/days the affected areas turn darker and then finally lighter brown as depicted in the middle of the picture. A few days later that branch is a lifeless light brown/yellow husk of a former lush green tree. Death has come.
   
   
7. You must collect fresh seeds from a mature tree to get good germination rate and viable seedlings.
   

   The notion that fresh seeds must be collected from mature sequoias for good germination is a myth; purchasing from reputable sellers is more practical and effective, as these seeds remain viable for many years.

   This one is a myth. First of all, you don’t have to travel to California to get the seeds. They are sold worldwide and as mentioned above are cheap, relative to the effort to keep them alive over next few years.
   
   Second, even if you find yourself in a park in California or the amazing Benmore Botanic Garden in Scotland, it would be counterproductive hunting for cones instead of enjoying the trees. Even if/when you see a cone next to a trail it doesn’t mean you can find more than just a few seeds inside of them. One time we got “lucky” when we arrived to a California park right after a big windstorm. There were branches all over before the park rangers could haul away the mess. In this case yes, there were dozens of cones fresh off the trees to get seeds from. Extracting seeds from cones is not as simple as one might think. Again, just a few seeds, not a big deal, but if you are somewhat serious and actually want to grow a sequoia you would need a few hundred seeds. Do yourself a favor - spend $10 and have them shipped. Be aware of Amazon/eBay scammers selling small packages of 10-20 seeds. You may get a few mostly damaged seeds with a whole lot of dirt. Go to reputable sources - they will be cheaper and drastically higher quality. Will mention JL Hudson again - highest quality, practically free seeds.
   
   Third, sequoia seeds remain viable for long periods of time. I still germinate 2012 seeds that were sold by JL Hudson for 2013 planting season. I got 1 ounce then (32 grams) that was about 6,000 seeds. They germinate just fine in 2023. So, don’t rush to a park, don’t get scammed by internet offers of 10 fresh seeds off unique cold hardy sequoias. Buy from reputable seed sellers and you will have a great experience. 
   

   

   Light brown sequoiadedron giganteum seeds purchased from JL Hudson

   
   
8. Sequoia seeds require organic rich soil. 
   

   Contrary to popular belief, sequoia seeds thrive best in non-organic soils like peat moss with perlite, as excessive organics can lead to disease and wilting in the early stages of growth.

   A dangerous myth. Just to be clear - mature sequoias can certainly take advantage of soil rich in organic matter. Seeds are not mature trees. They frequently catch diseases when first placed in soil. Countless little sequoias will wilt and die if placed in soil with a bit too much organics. On the other hand, pure peat moss with some perlite with NO organic matter works just fine for the first 6-8 month. Adding very diluted liquid plant feeder helps. Sequoia seeds have everything they need without any external organics to grow for the first weeks. It can not be stressed enough - first few weeks, months and even first years is not about vigorous growth but about keeping enough of them alive. They will still catch disease and slowly die at any age, very young ones with healthy 4-8 leaves will just drop dead over night - losses are inevitable and it's numbers game in our non-native climates, but introducing organic rich soil to seeds is just counterproductive.
   
   If you are in USA then I can recommend Miracle Gro "Cactus, Palm & Citrus" potting mix. It DOES have some organic matter in it so I spray Daconil periodically both on seeds and germinated plants to keep them disease free. 
   
   
9. Internet is full of misleading information on growing sequoias.
   Unfortunately this one is not a myth. As an example of misleading information on sequoias, here’s a screenshot from Quora: 
   
   
   According to this post, sequoias are "very slow-growing", you need to "collect seeds from a mature tree", the seeds of seqoiadedron giganteum are "dark brown", you have to plant seeds in organic rich soil, they require 30-60 day stratification and the most belligerent one: "it will be several years before the trees are large enough to transplant to their permanent location". These are all blatant un-truths about growing sequoias anywhere on Earth.
   
   So, definitely get your information from multiple sources and look for some evidence of actual experience growing sequoias. 
   
   Just to be clear, all that is wrong with that post - sequoias are some of the fastest growing conifers, you do not collect seeds from mature trees but buy them from reputable sources, seeds are very light brown, plant germinated seeds in non-organic substrate, no/little stratification is needed, be ready with planting in permanent spots within 2-3 years from germination, maybe 4 years, but that's certainly pushing it. 
   
   
10. More to come... Cold hardy varieties.. 
11. About JL Hudson. If you want good quality seeds at low price.  That's them. We can all be united under the banner of unifying love for trees.