Friday, June 12, 2020

Humboldt Lily Thieves and How to Grow Humboldt Lilies from Seed

Photograph of Lilium humboldtii flowers
Meet the tallest and (in my opinion) most spectacular of the native Lilies of California, Lilium humboldtii ssp. ocellatum! This species grows up to twelve feet tall, from an underground bulb, bearing up to 70 of these brightly colored lilies on each stalk. They are in flower now in secluded and protected places along streams in California. This photo is from a wild plant on the edge of the San Fernando Valley. These are plants best grown from seeds, and if grown from seeds do very well in local gardens (see Propagation further down).

Here is a photo of me standing next to a tall, but not remarkably tall, specimen.

What happens when people find beautiful or wonderful things in the wild? Anything can happen. Most folks look and admire and take photos and memories, then move along.

A few have other reactions. They are one reason these plants have become hard to find in the wild. On the same hike my son and I noticed some lilies had seemed to have been broken off and left to die. This made both of us sad, then we noticed the holes and we became much more sad. Someone was stealing the plants!

The reason this made us more sad is that these bulbs are not like Daffodils, and they do not transplant well. Often wild plants have become enmeshed in the forest floor mycorrhizal network, a criss-crossing mesh of living fungal strands. These strands are a nutrient and water exchange system connecting most of the plants in the forest. Remove the lily from the network and the lily usually dies of shock.

What to do? Propagate!

Grow them from seeds, buy them from nurseries that have selected plants that do well in gardens, and protect the wild ones wherever you encounter them. You can get them from the Theodore Payne Foundation in Sun Valley, for example (though until their new online store is operational on June 16th the plants and seeds are not listed on their website, you have to call).

If you get seeds, the procedure to start them may seem odd, but is pretty simple.

Get a zipper seal bag, add a half cup of vermiculite, your seeds, and enough water to make the vermiculite moist but not so wet that there is any water collecting at the bottom of the bag. Put the bag in a drawer in your room - I use my sock drawer because it is farthest from the window and I go to it every day, so I don't forget the seeds. The idea is to keep the seeds room temperature (or around 70 degrees Fahrenheit plus or minus a lot) for three months. Yes, three months. Check them once a week to see if any are beginning to grow small white roots (this is unlikely to happen, but does once in a while - the seed that grows a root can be planted now - skip ahead for it but leave the others in the bag until they sprout). This is called warm, moist stratification.

Now put the bag into the vegetable drawer of your refrigerator for at least two months - once again, check the seeds often. As soon as they start developing white roots, they are germinating. By the third month (90 days) take them out and plant them.

We use troughs that are 8" wide, 6" deep, and 15" long. Make certain there is at least one good drainage hole in the bottom of the trough, or the plants will rot after germinating.

The soil mix we use is simple: 3 parts Pearlite, 6 parts Coir (coconut fiber - be sure to soak the bricks and let them expand first), and 1 part clean 80 grit silica sand (sandblasting sand). Mix it all together while the ingredients are moist enough not to make dust.

Once mixed, we put a small scrap of aluminum window screen over the drainage hole, then fill the trough with soil to within about one inch of the top.

We sprinkle the germinating seeds from the bag out onto the soil surface, with the vermiculite they were stratified in, and then gently cover with half an inch more of the soil mix and water immediately.

Keep the troughs moist but not soaking wet - too much water is as bad as too little with this species. They like bright shade, no direct sun, and as cool as easily possible. They live in deep, shaded canyons most often in the wild. After their first year, let them go slightly dry (no baking in the sun or going bone dry) in September and October. They will often push new leaves and stems up in January of each year, though this can vary quite a bit. Leaves can die down as early as July or as late as late September. Once the leaves die down reduce the water - let the soil surface dry out (no more than the top quarter inch or so) between watering.

I've flowered them in four years from seed, and had really amazing plants taller than me in five years.


  1. Hello,

    Wonderful information!

    Can you post a photo of what the seed pods and seeds look like? I've only seen the plant and am curious about the seeds.

    Thank you!


  2. Thank you for this. someone sent me a box of L. humboldtii seed last year and i forgot about it till i found your article. I appreciate it!