Iris Doctor

By M. D. Faith

 

M. D.,

 

I have some seeds I saved from last year in the fridge. Do you chip seeds to increase germination? I read about that technique in The World of Iris, … but was unclear from the description exactly what you do when chipping.

I did save some Louisiana seeds, and they are something strange, tubular things that break into pieces with no discernible form as a seed. It's more like opening a colon than a seedpod. Have you had any experience with Louisiana’s there in Little Rock? … From James in Jacksonville, Tennessee.

You are right they do look something like what you describe. They are packed so tight in the three chambers of the ovary with some being flat and others round to triangular shaped making your unusual expression, a quite vivid description of the process of removing the seed from the pod.

 

They have a cork like covering over the individual seed, which give them the ability to float down stream, or drift away from the original parent clone. It also, I think, works to help deter germination immediately in nature, since I feel it must rot away, before much germination takes place, thus prolonging the period of germination, as a survival tactic, over two, three, or more years. This makes survival of the species more certain over time where extended weather conditions alternate between years of extremely dry conditions as well as wet conditions. That said I have observed seed push their first primary root right through the cork like covering sending up their first leave in the first year after falling to the ground.

 

I grow, and have grown, and started a lot of Louisiana iris seed, and I have experimented with scratching or scaring the seed coat, as well as chipping or nipping the end of the seed.  I have been unable to discern any better germination in the scared or nipped seed over those not scared or nipped. That is not to say others, who have had more experience than I do, might have had a better response to this treatment. However after chipping they become more vulnerable to rot and decay, and my bad experience with rot did lead me to stop the practice.

 

Here is my present method with which I have had quite good results. I peal the cork covering off with my thumbnail or a blunt knife to expose the seed. Some peel rather easy and others you can hardly get it off, but do the best you can to get off as much as possible.

 

After you peal the seed, soak under water for two to six weeks or longer depending on your schedule, changing the water every two to four days depending on temperature, and-or your energy level or inclination. Good germination occurred for me on some lots of seed that were soaked for as long as four to five months. The idea is to wash or leach out the inhibitors, which deter germination, and to plump the seed.

 

For me seed germinate better if not allowed to dry out after ripening. That is when the seedpod begins to crack open, gather and shell the seed. Then pealing the cork like substance off the seed, you can start your soak period, refrigerate in a damp medium in plastic bags, or you can plant directly in pots, or in the garden. Drying seems to encourage a deeper and longer period of dormancy with in the seed, resulting in a longer time until they sprout.

 

Place on top of a bed of sterilized potting soil or growing medium that is about one inch deep in a plastic or glass container. Do not cover the seed, let them lay exposed on top of the soil. The potting soil or medium should be saturated with water to the point you can discern the water level just at the surface.

 

Seal container with clear plastic or glass and place in full sunlight if possible. Germination is directly related to the amount of light the seed receive. I place them in a south-facing window where the temperature will very from forty five to seventy five degrees (F).

 

Check on them about every two or three weeks to be sure the moisture level remains the same, in the container, as when you put them down. They must not dry out. The seed need to remain plump and healthy looking.

 

Germination will begin depending on the variety from about a month to as long as two years (possibly up to five years or more), with most up with in a year. I generally let them grow to a height of about three inches, at which time, I gently add water to slightly flood the container, then grasp the leaves and gently tugging pull the seedling from the medium, being careful not to dislodge the seedling from the seed.

 

Pot them in a container with the seed flush with the surface of the soil, being sure there are no exposed roots, and feed with one half teaspoon of 30-10-10 Miracid to the gallon of water. Feed generously with this as needed to keep containers well moist but not soggy. In four to six weeks you can line them out, if they have made good growth, and have begun to fill their container with roots. Alternatively you can re-pot into larger containers, where you plan to grow them until first bloom, which will be in about 16 to 24 months.

 

My favorite tall bearded iris has a seedpod that is cracking open. You told me to harvest the seed at this time, so now what do I do with it? … From Mary in Little Rock, Arkansas.

 

My greatest success with tall bearded, or any bearded iris seed, has been to shell them out when the capsule has cracked revealing the pretty bronze colored seed. Plant them, directly upon shelling, into the seed bed which has been prepared to receive them, or into pots so prepared, covering the seed with about one-half inch of finely screened soil. Water the soil well and do not ever allow them to completely dry out, in dry period you must be very vigilant.

 

When planted into the garden, I cover the bed after planting as above with two thickness of newspaper with weigh on the edges, or the edges covered with soil. Then placing a one-half inch soaker hose, in a loop along the top about one foot apart, which is attached to a water source with a timer. The timer is set to soak the paper and bed until well saturated once a day during the hot dry days of August, September, and until the fall rains begin in October or November. Plunged pots can be treated in the same manner as above, or set in trays of water and covered with clear plastic or glass.

 

A few seedlings may sprout through the newspaper around Christmas time, but the later cold weather probably will not hurt them here in our area. I have had several seedlings up at this time with temperatures of 20 degrees (F.) or less on several occasions through the winter with little, if any, damage to the seedlings. The bulk of the seed will sprout in the spring, so remove the newspaper when they start to sprout rapidly in the spring. It seems to me, you get near 90 to 100 percent germination when handled this way.

 

Good luck to you both!