beckygardener said:Maurice - THAT is an excellent photo! A photo speaks a thousand words!

Thank you.

Let me wrap my head around this .... Daylilies produce new roots and fans on TOP of the previous year's growth. So the plant should be moving UPWARD in the soil, right? Yet some are being pulled down by their roots? Pulled down more than they are growing upward? Why would that happen is the big question! What eventually happens to the old growth ... it dies off?

Think of the daylily fan as being a stem that has been squashed down. For this case a normal stem has leaves on opposite sides of the stem (one leaf on one side of the stem and then the next leaf a little further up the stem but on the exact opposite side of the stem) and then at the very top and centre of the stem is the growing point. During normal growth the growing point only produces leaves but when the fan/crown/etc/? becomes large enough the growing point stops producing new leaves and produces the scape with any branches and flower buds. Once the growing point starts producing the scape it can never produce any more normal leaves for the fan.

If the fan does not flower that growing season then the growing point becomes a bud to produce next year's fan. And it is at the "top" and centre of the crown.

If the fan does flower then a new growing point must develop on that crown and it often/usually does at the base of one of the leaves closest to the scape. So again the bud is near the centre and top of the fan. As that bud develops it slowly shifts to the centre.

When a fan divides to become two fans then either two buds develop near the scape (one on either side of the scape perhaps) or buds develop at the bases of other leaves further 'down' from the scape.

The plant would be moving upward in the soil if older lower parts of the crown do not rot away or if those parts are not absorbed by the crown or if the crown does not pull itself down.

Yes, some plants could be pulled down more than they are growing upward. There might be many reasons why that might happen. When first planted soil is 'fluffy' and has lots of air spaces. With time the soil becomes compressed. A plant that was planted at an appropriate depth in fluffly soil might become too deep when the soil settled. Soil that has a lot of organic matter will lose that matter with time and lose some of its volume and again a plant might become too deep.

In the first figure below I have exaggerated the distance between leaves to emphasize that the crown is a stem and that as it grows and develops it increases in height. My apologies for the awful drawing.



In the second figure I have shown what is inside buds of some daylilies in the autumn.



A bud scale is a special leaf on the outside of the bud. It does not grow to the same size of a normal leaf; it stays relatively short. The leaves are numbered from 1 to 10 and they would grow in the next spring. Some time after the last leaf, number 10, grows out next year, the fan will produce a scape and flower. Then the new bud, number 11, could start to grow or it could wait until later that year or until the spring of the year after. As that new bud develops it grows larger and it often slowly shifts more to the centre of the crown.

Meristem is the technical term for a growing point.

Again, more illumination! And, based on the article referenced, it seems possible that the top-most ring of newer roots (the ones growing during any blooming season) can contract and pull some daylilies down further into the ground - I think they must be the ones that end up looking a bit like elephant noses or vacuum hoses with their creases (see photo)? The article noted H. fulva's contractual roots were found to pull the plant downward into the soil about 2 inches in 8 months time. At least, that's my understanding from the article...

chalyse said:pull some daylilies down further into the ground - I think they must be the ones that end up looking a bit like elephant noses or vacuum hoses with their creases (see photo)?

Yes, those are the ones.

Maurice - Well, I just learned something new today! Excellent tutorial about daylily growth! I found your diagrams very enlightening! Thank you for those and the information!

Tina - So as the roots age, they contract and that contraction causes the plant to be pulled further into the soil?

Exactly so, Becky! You can see in the above photo that some of those new roots are lighter - the youngest/topmost roots start out bright white, then more golden as they build up an outer "skin" while the fan and crown grow, then more brown as the roots toughen their "skin" further and contract, pulling the plant downward. After the scape has gone up and flowers bloom, that ring of roots then becomes very dark brown, empty, and eventually disintegrates below the crown (which also loses some of its bottom flesh). New uppermost roots begin to form again at the top and the process begins a new cycle.

So, the contracting stage of the root means that, having already extended fully down into the ground during the white/yellow stage, those brown-stage contractions alone can pull the entire plant further into the soil, even if the soil is more compacted.

Two inches downward movement in eight months, especially in established fans that are in fully compacted soil, could contribute to crowns sinking faster (overall) than any upward growth by the stem or top of the crown might offset. It reads as though there is a range of contractual root movement downward, anywhere from 1/2 inch to 2.5 inches in eight months, with an average of about 1.5 inches.

So I guess, then, that in addition to keeping clump size in check, the 3-5 year regimen of dividing and replanting helps to also keep fans from sinking to a point where too much of the growing stalk and leaves are in the ground and not getting the amount of sun they'd like (and may contribute to them responding by blooming less and having less vigor).

And based on the research article, it is possible that wider day/night temperature swings (more than 15-30 degrees between day and night), the more contracting activity may be going on. I'll be following Maurice's outline to test vigor and performance in extreme prolonged temperatures that fluctuate only 10 degrees or so between day/night next summer (we have 2.5 months above 100 degrees with little day/night fluctuation and 10+ hours of full-on unshaded sunlight). My reasoning, after seeing some more robust fans in my garden that were sunk a bit deeper, is that there could also be some beneficial aspects to allowing fans in those circumstance to go and stay a bit deeper - to keep their crowns and roots cooler during the long summer heat wave. Its possible that the growing stem still needs exposure to the sun more than the roots need cooling ... but it will be neat to try it out and see what happens.

This was most interesting. Thanks everyone.

I'm going to have fun with this! Last Thursday we had 3.7" of rain, exactly 3 days after I had finished dividing and planting. Oh, there may be more significant rain on the way on Tuesday/Wednesday. Anyway, the plants are firmed into the compacted soil better than I could ever do! I water them in well after planting, but don't concentrate on firming the soil between the plants.

My daylilies dig themselves down about 1.5" during the summer. They are in boxes with a soiless mix--just peat, ground pinebark, and perlite. I fertilize heavily with manure and palm fertilizer plus some other stuff I have around. Probably that fertilizer on the new plants flushed completely through the box after that hard rain. That means that the queen palms got fertilized. Being on the beach, our temperatures are moderate for FL. Usually no more than 85 degrees in the summer and haven't frozen in quite a while. During Dec-Feb 40's are common. Compared to Orlando temps, we are substantially cooler in the summer and substantially warmer in the winter. Fairly mild.

Now, if we can get the wind to back off a bit (20-25 mph + 35 gusts), then I can spray for aphids and the daylilies would be oh-so-happy!!!

Arlene - My plants, too, were very happy with the rain we got recently! I am further south of you on the east coast of FL. (I am just north of Vero Beach.)

I would love to see a photo or two your daylily garden bed boxes. I am constantly trying to find better ways to grow my daylilies. Though I shouldn't complain as mine grow and bloom well. But they are plagued with rust and pests from time to time. I would love to find a plant that isn't bothered by anything here in FL. Pipe dream probably....

alot of reading in this thread, I didn't read it all. I have had trouble with this. Usually it begins with me noticing a plant that is struggling. Generally it is a smaller plant, most often a 'new' one. They appear to dwindle away and I finally have a free moment and take a looksy. The crown is way under the soil so I have to dig it out and replant it. My theory, especially since most of them are small fans and newer plantings, is that the compost and looser soil I plant in, over a few months or a season, settles quite a bit and the roots/crown literally sinks. And of course the freeze/heave aspect causes the soil to loosen quite a bit around a plant that has not had time to develop a root system large enough to hold itself in place and after heaving, the whole thing sinks, a big rain comes along and washed soil over the crown even further and then come spring it can't grow right and starts rotting and looks puny--that's when I notice.