My desert willow seed germination experiment

It wasn’t a scientific test by any measure, but I played around with some desert willow seeds that I plucked from a neighborhood tree and came up with some interesting results.

I’m a staunch soilless medium fan. I’ve had horrid luck with potting soil, compost and the like when it comes to seed germination. Damping off follows my germination efforts around like the grim reaper.

If you’re new to gardening, damping off is the nickname of a fungal disease that kills seeds and seedlings. If you’ve ever had a seedling sort of fold over, in the middle of its tender little stem, and fade away, it probably suffered from damping off. Sometimes fungicide soil drenches or dusting seeds with fungicide powder works. Sometimes it doesn’t. Germination media without soil works for me. Usually.

Anyway, back to the desert willow experiment

My sample size included a whopping eight desert willow seeds. These seeds look like something you’d find in a piece of really good whole-grain bread: rather flat, oval and brown. The only difference between the seed in bread and that of the desert willow is that the latter is surrounded by fuzz and it has wings.

The first two seeds — hereafter known as “Batch 1” — got wrapped in a damp paper towel, placed in a sealed plastic container and left in the refrigerator for two weeks. Why two weeks? Couldn’t tell ya.

The next two –“Batch 2” — were pushed into a pot of coarse sand, placed in a lightly shaded area outdoors.

Batch 3 ended up in standard, but high-quality, commercial potting soil, placed in the same area as batch 2 .

The final set of seeds were direct seeded into the garden, covered with sand and watered once a day (it’s super hot out right now).

We have germination

Desert willow seed germination turned out to be as easy as I thought.

The only germination that has occurred is from batches 2 and 3. Batch 2 — the desert willow seeds planted in sand — germinated within three days. Although batch 3 — those sowed in potting soil — took two days longer to germinate, they are stronger and taller than those in batch 2. And, despite the somewhat shady area, one of the Batch 1 seedlings has what looks like leaf scorch on one of its tiny leaves.

The only difference in the desert willow seeds’ pre-germination treatment is the planting medium: potting soil versus sand. The difference in the seedling’s vigor, therefore, may be the result of several issues. My first thought is that the desert willow seedlings are stronger and taller because of the fertilizer typically included in commercial potting soils.

The extra moisture-holding capacity of the potting soil may be another reason. Although the desert willow is, as the name suggests, a desert dweller, it flourishes in the desert’s washes, ditches and depressions — anywhere that water gathers, even if it quickly drains away. Perhaps the seedlings’ roots grow stronger, quicker in a somewhat more moist environment than coarse builder’s sand provides.

Other than the different soils, the four seeds were from the same pod, planted in the same amount of sun, in the same temperature and provided the same amount of water.

Desert willow trees are common in the southwest: Texas, Arizona, California and Nevada. Their ferny foliage and orchid-like flowers provide striking relief to a desert backdrop. If you plan on germinating desert willow trees — which I have seen for sale at online retailers for $50 — my advice is to sow them in a good potting soil and frequently check the soil moisture. Once they’re successfully propagated they’re quite drought-tolerant.

Worked for me.

Photo Courtesy: Garlandcannon/Flickr.com