Udo isn’t a plant we often talk about in the Western world. But it’s a spectacular plant that looks beautiful, and you can eat it, too. It’s the perfect plant in my book.
On top of that, you can plant udo in places in the garden that are too shaded for other plants.
This large edible is perfect for food forests or survival gardens. Plant it once and let it come back year after year. Plus, it’s so attractive in the garden that you can grow it as an ornamental. Few people will even know it’s edible.
You’ll love growing udo. Let’s dive in.
Table of Contents
What is Udo?
Udo (Aralia cordata) is a herbaceous perennial native to East Asia, including China, Korea, and Japan, where it is prevalent. It’s part of the Ariliaceae family, making it a relative of ginseng.
This large plant can reach up to 10 feet tall in shaded areas of your garden that many other plants won’t tolerate. This impressive growth occurs each year after it dies down from the last season, so it is a swift grower.
Udo will die back to the ground each year before re-growing in summer to its mature height and width, which can be ten feet, depending on the type. The new shoots are edible, making this an abundant provider from when it emerges to when it dies down.
Plant udo in USDA Growing Zones 4-9.
In Japan, udo is often foraged in the wild. Since it’s not usually present in the wild in the US, you can grow it. In fact, many people in North America are growing udo without realizing it is edible. You might see it sold under the name spikenard.
Japan has two categories of udo: yama (mountain) udo, which is foraged from the wild, and nanka (softened) udo, which is cultivated underground. Softened udo is pale like bean sprouts and has a soft texture.
Gardeners are growing udo in the Tokyo area, where it is known as Tokyo udo and is a particular delicacy.
Nanka udo is a delicacy and must be grown in specific conditions to produce the flavorful, tender stalk. It’s commonly eaten in stir fries, ramen, or tempura.
Best Cultivars of Udo
Typically sold simply as the species, a few cultivars have been produced over the years. Growers tried introducing udo to the market in the early 1900s, but it never caught on in a big way.
‘Sun King’ is, by far, the most common cultivar. It’s also commonly called spikenard or Japanese spikenard.
Introduced to the US from Japan, ‘Sun King’ has a striking golden color to the leaves, but the more shaded the area, the greener the leaves will be.
‘Sun King’ is smaller than full-sized udo, and is often used in the garden as an ornamental. It usually grows to three feet tall and wide.
How to Propagate Udo
It can be a little fiddly when you first propagate your udo for the first time. Once this is done, though, it will reliably return year after year.
Seed
Udo seeds need at least three months of cold stratification to replicate their natural environment in the mountains of East Asia. So long as you don’t mind stratifying, growing udo by seed is an easy task.
There are two ways to do this, but if you live in an area with consistently cool winters, try the first one, as it takes advantage of the natural conditions.
In a Cold Frame
If you have a cold frame, growing udo seeds will be a cinch. Sow seeds in early fall into moist seed-raising soil. Sow about a quarter of an inch deep and in individual cells. Cover lightly and keep this moist until germination.
Place these pots in a cold frame where they will be exposed to near-freezing temperatures. Germination should occur in one to four months once the temperatures reach an average of 65-68ºF.
When the seedlings are large enough to be handled, transfer them to larger individual pots and keep them in a shaded area of a greenhouse or in a cool room with bright, indirect light.
Keep them here for at least the first winter, since transferring them too early to the garden can cause them to fail.
Plant outside in their permanent position in late spring or early summer as long as the plant is at least ten inches tall. Be sure to harden the plants off before putting them outside.
Hardening off means taking the plant to its permanent location for an hour and then taking it back inside. The next day, take it outside for two days. Add an hour each day until it can be in sun all day.
In the Refrigerator
If you live in an area where the winters aren’t cool enough, or the cool weather is inconsistent, stratify the seeds inside. The process isn’t difficult, but it will take up room in your fridge for a long time.
Place a growing medium, such as peat moss or fine vermiculite, in a sealable bag.
Put the udo seeds in the medium, moisten it so it feels like a well-wrung-out sponge but not any wetter, seal the bag, and place it in the refrigerator. Keep the medium moist and ensure mold doesn’t grow.
Usually, the temperature in the fridge is cool enough to stop mold, but if you see it forming, remove the moss, spray it with a 10% bleach and water solution, and place it in a new, clean bag.
Leave the seeds there for three months before sowing them in seed-raising medium and placing the pots in a cool glasshouse or shaded area.
As with the cold frame method of growing udo seeds, plant out in late spring to early summer after at least one winter.
Root Cuttings
Take root cuttings when the plant is dormant. It will die back in the winter, so do this before the ground gets too cold.
Carefully dig around the crown and lift the root system. Udo should come out in one piece, or use a clean, sharp shovel, spade, or knife and divide what you need.
Make sure you don’t take more than a third of the plant, whether cutting from the ground or removing roots once out of the ground.
Replant the mother plant as soon as you have cut off what you need.
Choose roots about the thickness of a pencil and cut six-inch pieces. Cut as close to the crown as you can. Cut one end horizontally and the other end at an angle. The angled end is the new bottom.
Store upside down in damp sand in a cold frame. In early spring, plant in pots and water well. As with the new plants described above, keep them in a greenhouse or cold frame through the first winter and outside in the following spring or summer.
Suckers
Udo will grow suckers, and these can be cut and propagated to make new plants. Take these cuttings in the spring and remove them with a little bit of root or stem attached, if possible. Plant the cuttings in prepared soil.
As the plant goes into dormancy in winter, cut any suckers from the plant as close to the crown as possible. Replant the suckers straight away in the ground. This method is not perfect, but some of the suckers will survive until the next growing season.
How to Care for Udo
Udo is one of few edible plants this size that loves shade and can take up one of those shady spots in the garden many other plants would never grow.
Dappled sunlight is best, but a spot in more shade is okay if some light gets to the plant. Regardless, it should get no more than four hours of direct sunlight throughout the day. The young growth early in spring is frost tender, so choose a location where it can be sheltered from frost and wind.
Poorer soils tend to produce tougher udo. You should be growing udo in loamy, rich soil with a pH between 4.0-7.5.
Udo doesn’t require a lot of feeding as it will keep growing without fertilizer. But it can help improve the quality of the leaves and roots. Dig a good quality compost into the ground before planting, and you shouldn’t have to feed it again unless you choose.
Keep the soil moist but not overly wet. The soil is shaded areas tends to dry out more slowly than those in sunny spots, but keep an eye out for the surface getting dry. Once the surface dries out, add more moisture.
You don’t need to prune growing udo as you can harvest as often as you like and it will die back each year. Remove any dead, diseased, or damaged branches. Other than that, let your growing udo do its thing.
Best Companion Plants for Udo
Udo is a great plant for a food forest. Try other edibles that tolerate shade, but remember the size and spread of the udo plant.
- Elderberries
- Raspberries
- Cilantro
- Dill
- Ginseng
- Lovage
- Wasabi
- Chickweed
Harvesting Udo
The long shoots can be harvested through spring, especially when young and tender. The skin of the shoots has a bitter taste to many, so it is best peeled off. Late in the season, this skin becomes more woody. The pith that remains has a crisp, citrus taste.
Harvest the leaves in summer.
The young shoots with leaves can be used in tempura or salads.
Soak the pith for a couple of hours before cooking it in a mixture of one cup of water and one tablespoon of vinegar if you think it still tastes bitter.
Problems and Solutions for Growing Udo
This is a tough plant, and few things affect it. It’s rare that you’ll encounter trouble when growing udo. But nothing is immune to everything, so you do need to keep an eye out for a few issues just in case:
Spider Mites
Spider mites are a common garden pest. We have a great article on them to help you identify and get rid of this pest.
Black Spot
Black spot is a fungal disease that attacks many species in the garden. To avoid it, try to get as much airflow and gentle wind as possible through the plant.
Remove any stems that look like they may be getting spots on them. Keep the plant well-watered. Use neem oil if necessary, though do this late in the day when the bees have retired for the night.
Yellowing Leaves
Udo is affected by few diseases, so yellowing leaves usually mean the plant isn’t receiving enough water.
Even though it suits shady areas, which are naturally moist locations, keep an eye on the soil and don’t let it dry out. Keep an eye on the soil, especially in windy conditions and when rain hasn’t fallen recently.
Using Udo
Now for the best part of growing udo.
Treat the shoots like asparagus. Make yourself some tempura or bake them in lemon. You can stir-fry them with some miso, sake, mirin, and rice vinegar to taste for a fantastic side dish.
The leaves can be used in lots of different salads. Pluck them as you need them.
The white fleshy roots can be eaten like a parsnip. Bake, boil, or roast them. They’re fantastic in soup or boiled and tossed in some mayo and umeboshi.
