Fall is a great time of the year for seed saving. Our plants have spent their time over the summer building up energy to produce seeds which will one day sprout, grow, and create new plants. Seedlings are essential to the diversity of a species. When open pollinated plants share their genetic makeup they can pass on variations in their gene code that can help the species fight off diseases and become stronger over time. One of my favorite trees to collect seeds from is the redbud or Cercis canadensis.
Redbuds bloom with purple flowers in the springtime that are very attractive to pollinators. Redbuds are legumes and produce their seeds in bean-like pods. The flowers can grow on the branches and trunk of the tree and eventually produce a bumper crop of pods. Redbud trees are a small understory tree that would be a great native plant selection for small yards. They are large enough to eventually create shade and small enough that they won't overtake powerlines and create issues.
When collecting seeds from a redbud just remove a brown redbud seed pod and peal the string part of the pod. It's very similar to a string bean in structure. When you do this the pod splits open very easily, revealing the actual redbud seeds inside. Collect as many seeds as you want to save.
After you have collected the seeds check them for viability. Just place the seeds in hot (not boiling) water. Redbuds have a hard seed coat that will need broken down and the hot water will help with this. After a few hours of soaking any seeds that are floating can be discarded as they are likely to not be viable. The sinking seeds are the ones to keep.
Save the redbud seeds in a bag of slightly moist sand and place in the back of your refrigerator. You could use any time of container that will keep them sealed until spring. Redbud seeds need cold stratification
to further break down their seed coat and simulate the winter cold to help the seed germinate in spring. Once spring arrives you can sow the seeds directly in the ground where you want them or plant them in pots.
Before planting it may be helpful to nick the seeds slightly with a knife or nail clippers so that moisture can reach the embryo easier. The cold stratification helps but the seeds may need additional help from a technique called scarification. Scarification is where the seed coat is damaged in a way that will allow moisture to reach the embryo inside.
One trick I have used to speed up germination is to scarify the seeds then place them in a moist paper towel inside of a plastic bag for a couple days. I usually put the bag in a warm place like on top of the fridge. After a few days the seeds should have germinated and you can sow the seeds that have roots. It may take 7-10 days or more before all the seeds can germinate so be sure to give them plenty of time.
Redbud trees can be very hard to transplant from one that is sown in the wild. By saving the seeds you can grow a tree and plant it right where you want it to be. Special varieties of redbuds like 'Forest Pansy'
or 'Lavender Twist' won't reproduce the exact same tree from seeds. Cloning or grafting is necessary for those varieties.
So go out and have fun collecting seeds this fall!