In the Czech Republic where I live there is a long tradition of making braided and woven objects out of willow twigs and I thought to myself that it shouldn't be that hard to make the Stormbreaker's handle using a similar technique and it turns out it was quite easy :)

This instructable will be separated into two parts because I expect not everyone will want to plant their Stormbreaker.

making the handle out of woven branches
planting Stormbreaker and growing a Groot :)

Supplies

Making the handle

branches
gardening scissors
string
Strombreaker axe head

Planting Stormbreaker

water
vase
soil
planter
water retaining material (optional)

Step 1: Axe Head

You can use any metod you like to make the axe head. I prefer 3D printing. This is the model I used: https://3d-mon.com/3d-model/groupe/unisex3dprintmodel/stormbreaker-thor-axe-head-only-plant/

I printed it with PLA Vertigo Grey from Fillamentum

The model has been updated since the time I printed it so it looks different to what I have in the photos.

Step 2: Collect the Twigs

You want to use branches that are young. There are many types of plants that work with weaving and one of the best are willow branches. They are very flexible and they have long straight branches without side branching. You can use other species of plants that fit the same criteria. It's best to collect last years branches in the spring. After you cut them from the tree just slide your fingers over them to remove the leaves.

Step 3: Weaving the Head

I started with tying the tips of the branches with the string. This is going to be hidden under the branches later and seems like this easiest way to make sure it stays manageable while weaving. I put the knot below the head and put half the branches over and half under it. Then I just took the branches one by one and twisted them around the head. Sometimes I would go through a loop created by the previous branch. I stopped when I felt the head was held securely in place and covered enough. At this point the vines are all pointing down and covering the tied ends.

Step 4: Braiding the Handle

Stormbreaker doesn't have a lot of branches going over and through each other on the handle so I tried to keep that very basic twisting them though each other only a little bit. But if you want to go a bit crazy with a cool pattern, go for it! I tied it at the base with the string for now. Trim of the ends to of the longer twigs.

Step 5: Bark Grip

I then made the grip from the soft bark of the willow branches. I just took scissors and made a cut along it to start it off and then simply peeled it by hand. It should come off quite easily. If it's not coming off for you then you might just not have the right kind of plant for this part or it's not a good time of the year (trees are running with watery sap in the spring which makes it a lot easier).

When you get the bark of in nice long strips the rest is pretty easy. Tie a knot where you want to start the grip and work it around the branches moving it up or down with each turn. Try to make it tight. Tie another knot and the end an tuck the loose ends under the grip. That will work better then cutting the end off because it has a lower risk of getting untied later. If you feel like it's secure you can cut of the string now.

Step 6: Stormbreaker Is Created!

Well done, that's it! Stormbreaker is now finished!

Step 7: Part 2: Growing Groot

We all now how Stormbreaker was created. When you think about it, if you plant Stormbreaker you should be able to grow your own Groot right‽ That's what we're going to try to do next :)

Step 8: Starting the Roots

You should be able to start the roots easily by planting it into the ground and keeping is moist but I wanted to make sure and also see the process so I started the roots by leaving it in a jar of water first. Leave it there and watch. You don't have to check every five minutes though :D it's going to take a while.

You could also apply root stimulator to the twigs but willow water is actually used as a natural root stimulator to starts other plants growing roots so if you used willow branches then you should have that covered ;-)

(I first let it dry for about a week before thinking of planting it but it would definitely work out even better if you don't do that. More of the branches would catch roots. This photo is after about 10 days in the water.)

Step 9: Sprouting Leaves

Keep an eye on it, maintain the water level and after about a month it should be good to go. You should see new leaf growth. The last picture is after 2 months.

Step 10: Planting Equipment

To plant it you're going to need a pot, soil, a trowel and I also like to put something that will keep a bit of moisture (like expanded clay pellets)for when I forget to water it. This time I used some pieces of a broken ceramic pot for that purpose. You should have a platter to put under the pot to hold water but I didn't have that around.

Also, have the right idea and wear the brown pants :D

Step 11: Plant It

I put the ceramics at the bottom and then filled the rest with the soil. Then I made a hole for the plant. Put it in at least to the depth that the water level was at. Cover it with more soil.

Step 12: Water It

Compress the soil well but be careful not to damage the roots. When you've done that water it really well. At this point you can't use too much water unless you flood away all the soil with a hose :D

Step 13: Maintaining

You can let it grow naturally if you want. I'll leave this up to you but I wanted to keep mine tidy and have it woven as cleanly as possible. When the branches grew out a bit more I tucked them all back under the old branches and even managed to tie the big one all around the head. I used some string to hold some of the branches that wanted to come loose.

Step 14: Watch It Grow :)

There it is! I'm really happy with the result and I hope I'll be able to keep it alive :D

I made this one last year and it's starting to have new leaves after the winter. The 3D model has been updated since the time I made it so this year I want to make a smaller one and I'm excited to see how that one will turn out.

This one is constantly transforming as it grows and I love seeing it. I hope you will be as happy with yours :)