Hello fellow naturalists! I’ve recently gotten into the propagation of a few woody plants whose seeds are readily accessible near me: Gleditsia triacanthos, Quercus rubra (and hopefully Q. macrocarpa in a few years), Celtis occidentalis, Ginkgo biloba and a Crataegus I couldn’t ID to species. I have already prepared acorns, hackberry seeds and ginkgo “nuts” for stratification, but I’m unsure how to germinate Crataegus seeds. What methods have you employed (be it at work or at home) to germinate them? According to my research they require 3 months of warm stratification at 15-20 C followed by another 3 months of cold stratification at 0-5 C, and can take up to 18 months (?!) to germinate. Can you corroborate this?
Don’t hesitate to bring up any seed germination efforts of yours. I’d love to read about them!
Since you invited a little latitude into your discussion, I’ll chime in on what I do know. The honey locust seeds just need to be stored in a cool spot for the winter months. A refrigerator, shed, or cold garage space will do. I found that bringing a cup of water to just below the boiling point, removing from the heat, then dropping the seeds into and letting it cool overnight will break the outer seed coating and they’ll readily germinate. Some people scarify them with a knife too. The red oak acorns will also need cold stratification. You want them in some sort of medium that will keep them from drying out. Moist (not soggy) sand or potting soil works. Some people use sawdust but I have no experience using it. Burr oak is in the white oak group which will readily sprout in the fall, shortly after dropping to the ground. No cold stratification required, just keep the acorns protected from predation, and harsh cold temperatures if direct sowing outside. A layer of leaves or mulch over the buried acorns will suffice. Check your acorns over well for signs of weevil damage before investing time into them. It can be disheartening come springtime to find out they’ve been rendered out of service. Sorry, no experience here with hackberry (rare-ish here in Connecticut, in my travels anyway) ginkgo, or Hawthorn.
Thanks for your quick response! Like you I’ve found that soaking honey locust seeds in near-boiling water left to cool overnight is enough to break their outer seed coat. No need to store them in a particularly cool spot either (although low temps may inhibit fungal growth). I think adding a little half decomposed organic material can help introduce Rhizobacteria and facilitate germination as well. I say this because I found 6 seeds I had tried sowing in potting mix germinated in my compost bin mid-july.
Also I didn’t know about the germination process of white oak acorns. Good to know
I haven’t personally tried Crataegus seeds yet but I’ve coaxed others with similar stratification requirements into germinating. One of the books I have only has one Crataegus species listed and says it requires double stratification: four months warm followed by four months cold. There seems to be conflicting info though with some saying only cold stratification is required. It is recommended to remove the seeds from the surrounding fruit for storage and not store them longer than a year as they lose viability rapidly. Another book says propagation is “moderately difficult from seed” in this genus but does not provide any details on stratification requirements.
I’ve been able to get fringetree seeds to germinate in less than a year using double stratification. They have a pretty tough seed coat, so I filed them a bit to create weak points before soaking them overnight and placing them in a closed container with damp peat moss in a warm place. After that, I planted them in moist potting mix and refrigerated. I had several germinate and one survivor past 1 year, which is now planted out in my yard and has been blooming for the last two years already.
You might just sow some hawthorn seeds in a pot and keep the pots over two seasons. You might get some germination in the first spring and some in the second spring. One issue might be that the pots shouldn’ be allowed to dry out, which would tend to happen over long periods of time when watering is not likely to be kept up with. Keeping pots over multiple seasons consistently moist could be difficult in areas with prolonged dry periods, but a shady area near a hose where you can spray them occasionally might just be enough. Another method is to keep the pots in trays that can be wrapped in plastic or covered with plastic lids.
Thanks for your reply! Most often the issue I encounter when trying to germinate seeds is fungal growth as a result of overwatering, as opposed to underwatering. However, this winter is the first where I attempt to cold stratify seeds outdoor, and thus far I have not watered them much, finding rain and snow to be more than sufficient.
Do you have experience propagating Juglans nigra or other trees by cuttings? I’ve picked up 2 healthy stems and wonder if they’ll actually develop roots after application of IBA rooting powder
No idea about propagating Juglans nigra from cuttings, but I would imagine that could work. I have a tree and enough squirrels that I get saplings popping up all over the yard. I find the most critical thing about transplanting them and keeping them alive is to take care not to damage the long tap roots they form.
I’m not the best person to advise on propagation by cuttings. I have done a little bit of this type of propagation, but not with that species. I did learn that you should follow proven advice that is specific to the species you are propagating, from people who have done it successfully with that species, or secondary sources that rely on actual experiences. I have grown walnuts from seeds, which seems like a reasonable thing to do given the abundance of seeds, easy germination, and the relatively good quality of the nuts that can be expected from seed-grown trees.
My general rule with trees in rosaceae like crataegus and malus is to sow the seeds in late summer, keep them outdoors in frost etc over winter and they should germinate next spring, but leave them another year just in case. I have germinated a couple of species of crataegus, they shouldn’t give any trouble.
Like you I’ve found that soaking honey locust seeds in near-boiling water left to cool overnight is enough to break their outer seed coat. No need to store them in a particularly cool spot either (although low temps may inhibit fungal growth). I think adding a little half decomposed organic material can help introduce Rhizobacteria and facilitate germination as well. I say this because I found 6 seeds I had tried sowing in potting mix germinated in my compost bin mid-july.