How to Grow Tulip Trees, Liriodendron tulipifera
Tulip Trees, or sometimes called Tulip Poplar or Yellow Poplar is a large stately deciduous tree. It can reach heights of 150 feet or even more. Although it is sometimes called "poplar" and it's lumber resembles poplar wood, it is a member of the Magnolia family. USDA Plant Fact Sheet on Tulip trees, pdf file
You often hear of old houses being trimmed with "gum wood", this is often tulip tree lumber stained brown. The lumber is commercially important and used for the frame of furniture, base for veneer, musical instruments, cabinetry and any place where an easily worked stable wood is required, particularly when strength is not critical. The wood is relatively inexpensive and tends to be quite bland looking so it is not used where appearance is important.
Because it is not so strong and is not particularly rot resistant, it was not used a great deal for boat building. An exception to this was it's use in dugout canoes where it's ease of working, stability, and the availability of large pieces are an asset.
Why Grow Tulip Trees rather than other trees
Tulip trees are handsome!
With their large shiny leaves and pleasant pyramidal shape it quickly looks nice and fills up a empty space with green. It's a lovely tree.
The photo is of a 7 year old plant. It is about 15 + feet high already and provides usable shade in the summer.
In the spring the yellow orange flowers add some colour and in the fall the tree turns a rich golden yellow.
Tulip Trees Grow Fast
This series of photos shows my little Tulip Tree at age 2 to 7. It is in good soil and I've kept it watered. It has grown from a little seedling to a 15 plus high tree in 5 years.
Being a fast growing and eventually large tree, means you have to think about where you are going to put it. It will want space to grow and you don't want to be in a position of having to cut it down only a few years after you put it in because it has overgrown it's welcome.
Trees are often planted as privacy fences. This is a very good use for a fast growing tree but be prepared to cut down some of the trees if you plant them close together at first. Stay away from power lines.
Because they grow so quickly, tulip trees are sometimes used to reforest an area. When planted with other trees in a mixed planting, it will grow faster than many other species and will shade and slow down its neighbours. Be ready to go in and thin the Tulip trees to give the other trees a chance. This is sometimes done in order to get a wood crop from the culled trees, leaving the remaining trees as a forested area.
Eventually the tulip trees will flower and produce seeds
At age 7, at the end of June, my tree produced it's first flowers. You can see a flower bud in the first photo, upper left corner. These flowers attracted the usual pollinators and hummingbirds, after a few days the petals fell off and the seed pod was left behind.
Many cultivars have been developed and Arnold is one of these. Unlike the regular tulip tree which grows as in a pyramidal shape, Arnold grows in a columnar shape and makes a tall narrow tree. Like the regular tulip tree it grows quickly and produces the characteristic tulip shaped flowers, but it takes up a lot less space on the ground. It grows as tall though.Backyard Gardener page on Tulip tree is very complete.
The photo is of a tree I planted this spring. It is flowering although the flowers are not very conspicuous. I estimate it's about 5 years old.
There are many people selling seeds, here are some Amazon links for some who are getting better reviews.
In Canada:Tulip Tree Seeds in Canada
Small trees are easier to start with: Small tulip tree Seedling
Large Carpenter bee making it's way into the tulip flower.
There are quite a lot of seeds in the seed pod but not many germinate. I've bought 2 sets of 12 seeds and of these only 1 actually came up. It's hard to say if the seeds were too old or otherwise badly handled, or for that matter if I did something wrong, but it is not an enthusiastic germinator. According to the USDA, squirrels and birds including cardinals and finches like to eat the seeds.
Seed pods at the end of October are quite dry and starting to open and drop seeds.
Tulip trees are quite pest free
According to the USDA "Tulip poplar is unusually free from insects and disease. The yellow-poplar weevil, nectria canker, and fusarium canker are three of the more important enemies of this species." Many moths and butterflies will eat the leaves, including the gorgeous yellow Swallowtail caterpillar. I can't speak from experience because I have not had trouble from either of my 2 Tulip Trees.
Deer are said to like to nibble on them but my deer pass right by them on their way to the maple and particularly to the poor cedars that provide fresh greens throughout the winter.
This past winter I wrapped the hedge in burlap and it fared much better. These 3 guys show clearly how high the deer like to browse. I left them open because I like deer around. They can be greedy though.
In the fall the tulip trees turn a rich golden colour and keep their leaves for quite a long time. My tree still has most of its colour even after the hickories and walnuts around have gone bare. The tulip tree seems to be content having a walnut tree nearby. They are a bit more than 50 feet from each other.
In September I noticed a new bird in the neighbourhood. I think it's a gnatcatcher of some kind. It was checking out the underside of the leaves. When I looked I found a few aphids so I guess that is what it was eating.
Best Conditions to Grow Tulip trees
First it's no good planting tulip trees if you are in the North. They can tolerate zones 4 to 9 but I think that might be stretching it a bit. In Canada it is native to Southern Ontario on the south shore of Lake Huron, the north shore of Lake Erie, and the Niagara Peninsula, in the Carolinian forest. They can be found as far north as Toronto but they are not very common there.
Link to Canadian Tree Tours.org their website gives information on various species and where individual trees can be found, it lists a few individual tulip trees in Toronto Parks.
Tulip trees like nice rich well drained deep soil with regular watering. They can tolerate some drought and some swampy conditions.
Before you plant your trees prepare your soil as much as you can. This is particularly true for Tulip trees. Since my bedrock is only about 3 feet down at that spot and from a foot down it's mostly varying size rocks, I dug down as far as I could go and used a pick and shovel to get as deep a hole as I could. It took me the better part of a day to make a good hole. I also mounded my soil for a 4 feet circle before planting the tree. I filled the hole with lovely rich sandy loam. Every year since I planted my little tree, I've added a wider ring of topsoil. Don't pile up soil high against the trunk to make a volcano shaped mound, this will damage your tree. It doesn't like to be buried.
Without sunshine your tree will not do well. He likes a full sun location if he can get it.
How to get a tree
In Southern Ontario, although they are an attractive native tree, they are not readily available. They are quite rare in the wild as well. They make good lumber and have been harvested heavily. I'm not sure what the problem is but they tend to be expensive, if you can find them. I've gotten both of my trees at The Mill Greenhouse, Dominion Road, in Fort Erie Ontario.
They are easier to come by in the US. Here is an Amazon supplier: 1 Tulip Poplar Tree (Liriodendron tulipifera) 3 to 4 feet Tall
Growing tulip trees from seeds.
Lots of places will sell you Tulip Tree seeds. The trees produce quite a lot of seeds in the pointy seed pods. The seeds called samaras, have a wing and is like maple trees get picked up by the wind. The spiky seed pod is left behind on the tree after the seeds have distributed.
It's no use trying to plant seeds in the spring without first giving it a cold treatment. In order to germinate tulip tree seeds need 60 to 90 days of moist cold stratification, simulating winter.
I put my seeds in a handful of damp soil, and placed this in a plastic bag in the refrigerator for the winter. Don't ask about my fridge!
In the spring I potted the seeds and put them outside. Of the 20 or so seeds I planted in 2 trials, I only got one plant to germinate. It took over 6 weeks to germinate so don't give up.
They are notoriously tricky to grow from seed so don't give up and plant a lot of seeds. It would help to get seeds from several sources and in the fall when they are freshest.
This fall I will try again but instead of putting the seeds in the refrigerator, I will plant them in larger pots, put wire mesh over them to keep the mice and squirrels out, and leave them outside in a protected spot and see if that works better. To be continued...
Taking Softwood Cuttings
I've tried several times to take softwood cuttings without much success. So it is not a very successful method in my experience. In this last trial, I used a branch I had broken while mowing around the tree. It's quite brittle and can be damaged by rough handling or by ice accumulation.
I took my broken branch and cut it in pieces so that at the top I had a leaf or 2 and at the bottom I had cut just below a node, I removed the leaf that was at the bottom node and dipped the end in rooting hormone. Once you buy a jar it will last you a lifetime!
After cutting the larger leaves in half I planted my sticks in moist soil and put the pots in a shady damp area. I watered and misted regularly so it never dried up.
I've had the cuttings sitting in the soil for about 2 months now and it looks like of the 8 I took, only 2 seem to have taken. They are not very enthusiastic rooters but it looks like a possible way of reproducing the tree.
I think one of the problems is that they like quite a lot of light, but when a cutting is in bright sunshine it dries out too quickly to root. Maybe an automatic misting system would work well.
The method that is recommended is to take a cutting in the fall rather than spring. I'll try this come fall.
I expect that air layering would work well. Maybe just putting a low branch with a nick and rooting hormone under the soil while still attached to the tree.
This information is for general knowledge and entertainment. They reflect my experience in Southern Ontario.