Leschenaultia biloba from seed...

I have been trying to grow this lovely little tender shrub from seed on and off for several years. No joy. I have tried most standard seed-raising techniques. Has anyone ever succeeded with this of any other Leschenaultia species?

This is a neat plant. I see Sandeman has some for sale. I assume you have tried cold stratification, boiling water, soaking, smoke primer, hot during the day, cold at night, H2O2, Warm-cold-warm, gibberelic acid? and various combinations of the above as well as different germinating temperatures, different times of the year.

I am experiencing similar problems with another Aussie, maireana brevifolia, but it hasn't been that long. Fortunately I have lots of seed to keep trying.

How big are the Leschenaultia seeds? Big enough to scarify?

Haven't tried boiling water... will have a go at that. I kind of figured that as it is a plant of hot bits of Australia, cold treatment wouldn't be likely to succeed... Seeds are fairly small (about ½mm x 1mm), don't fancy trying to scarify them... also, I don't have all that many (about 40). One lot is on the surface of vermiculite, the other in a Deno-style coffee filter. Have tried cool treatment in the past, but nothing...

Have just thought that maybe highly fluctuating temperatures might do it as deserts can get fairly cold at night... Trouble is, I'm not sure I want the hassle of taking them in and out of the fridge every day for an unknown period without, at least someone having succeeded!!!

Thanks for the input anyway...

Have you ever tried the smoke primer? You can get them easily from FineBush People in ZA and they are not expensive. The smoke is embedded in a filter paper and you soak it in water to release it. I am doing a bunch of proteacae right now and they require it The literature indicates they need a temperature differential of twenty degrees and at least 51 degrees at night. The fridge is about 45 degrees and the propagator is 65-70. So I put them in a air-tight plastic container and move them morning and evening. It becomes a routine like making coffee and putting the cat out. No germination yet, though. It has been about two weeks. Very hard seeds under a seed coat.

The coral tree seeds will largely not germinate until you nick them, less so with the crotolaria, but it does improve germination rate.

It is possible that it just takes a lot of seed, some plants are like that, just low viability. I think that is why I can't get germination on the maireana.

That sounds very good. I will also investigate the smoke thing... The temperature differential sounds exactly right, will try that... Do you think that light might be a factor?

Regarding light, I would have thought that, in a desert climate, seeds that remain on the surface and hence get light, would dry out as soon as they germinate??? so I am not too convinced that that is a factor. (Still, many cacti need light so I am not sure that argument is a good one!!!?

The seedlings in the filter paper are green, so they must be getting enough light. I do use a clear container. Rubbermaid has one in the States that is just about the same size as the flat-bottomed, Mr. Coffee type, filter papers. I have tried some others but they were too small and the papers bunch up too much on the sides. This one has a red lid, is square with rounded corners. A lot of desert seed depend on flash floods to wash them down stream and cover them with sand, so dark might be good, though I have noticed very few seeds need dark to germinate. Most seeds push the root out first, then the cotyledon breaks free from the seed coat then the leaves come. The amazing ones for me so far have been the erythrina and corn. Corn can produce a root that is 3 inches long almost overnight and the coral tree seeds are so big, produce such big roots and plantlets so fast.

I use the filter paper method, but generally in the dark. It's really tricky as some seeds need a *maintained* temperature to germinate and others need the fluctuations you already mentioned. Most of my 'warm' germinators simply sit in an old coffee tin on the top shelf in our kitchen - as that is the room with the lowest temperature variation. The cold ones sit in the bottom of the fridge. I have the entire 'salad bin' to myself - loads of filter papers and about ten small pots - for seeds that I know need light and 'pre-warming' before the cold phase. Many of them are gentians and primulas.

I have had some quite good results with cold germinators lately - dodecatheons, camassia, ixilirion. Then I have to figure out where to put them after they germinate that is cool enough and light enough that they don't get too much of a 'temperature shock'.... The big challenge is still Hellebores which I can never seem to get past the first leaf stage...

Incidentally, I have just figured out the solution to a problem that I had regarding the filter paper method. Quite a lot of species germinate over a period of weeks and that means decanting the germinating seedlings to pots over a period. I can't afford (the space more than anything) to give every germinant its own pot, and often there aren't enough for a whole tray of 'cells'. In the past I was forever slicing up one seedling while planting another in the same pot. Now I have figured to put a large label with a diagram of the top of the pot. I put an 'x' on the diagram corresponding to where I have planted the seedling... Seems to work fine.

(The Leschenaultia seeds have now gone to the fridge for the night!)

I found some weatherproof stickers and just put the plant number on it with permanent ink and stick it to the side of the 6-pack cell. That way one six pack can have 6 different plants in it, if need be. When I go through the filter papers, I just plant them as they come. Since they are all going to get moved up shortly anyway and get the same conditions after germinating, it really doesn't matter what order they are in. That way all the flats have plants in them, no wasted space. After a week or so, I start hardening them off. Then they go out with the rest of the seedlings to get upsized. It speeds up the process and makes the germinating chamber (Seed Palace) more efficient, not that I really need any more plants.

When I got all the seeds and put them in the computer, I put down a column for germinating instructions. The cold germinators haven't been tackled yet. I did a bunch of the easy ones, the soakers, and the smoke primer ones. The next bunch are the alstroemeria, the cold stratifiers, and the really weird ones. My wife is pretty territorial about the refrigerator, so I either have to get my own, or spread out the process. I could use the office refrigerator, which is probably what I will do for the long-term storage and stratification.

I starting using sheet pots that break into small 6-packs, they are flimsy but they do not take up a lot of room. Seventy-two cells per tray. Seedlings can get pretty good sized without getting too rootbound. I was using the 128s but that is quite a rigid format, you end up throwing a lot away or having lots of empty space. I am not sure how long they will last, but I should be able to get two years out of them.