Thursday, September 15, 2011

Green stems on lily bulbs mean - don’t dig quite yet!

The Vine Maples on our farm are beginning to turn lovely shades of red and orange and we'll soon be digging our main crop of lily bulbs.  Lilies need their leaves to build up the bulb for next year's bloom and much activity is happening underground after flowering.  A few out-of-place lilies in the test rows have been gently transplanted (while still green so we could I.D. them) into Dianna's garden in order to save them for continued observation.  Once their stems are mature, lily bulbs do not come out of the ground with their names stamped on the side, so it was necessary to move them while the bulbs were still depleted from flowering.
 (Go to Emergency Transplanting if you also need to move lily bulbs out of harm's way before the stems have begun to yellow, which indicates they have returned to dormancy. For normal digging and transplanting after lily foliage has turned from green to yellow, go to Fall Transplanting)

The two Asiatic lily bulbs with green stems shown in the photographs were blooming as an upfacing orange variety in a row of 300+ ‘Hiawatha’ - which are a deep red, outfacing Asiatic.  In a commercial planting it is not feasible to simply tag a stem; they have to be hand dug early because tags can be lost when bulbs are mechanically harvested and the mature stems become separated from their respective bulbs.  Furthermore, if that row is being used for propagation (scaling) then you have just multiplied the number of incorrect lilies in the field.
To produce a magnificent stem above ground, lily bulbs use stored food in their scales (segments that make up a lily bulb) and gradually become smaller and smaller until they are only a fraction of their original size when the flowers are ready to open.  This is why you need to provide another dose of fertilizer (low nitrogen formula like veggie or rose food, 5-10-10 or similar) during bloom; your lilies need more nourishment to reset themselves for next year.  Bulblets – genetic copies of the parent bulb – are produced underground along the stem and also require nutrients.  Ideally, the first application of fertilizer each season is spread around the new sprouts when they are just a few inches tall, but if you have not fertilized at all this year and the stems are still quite green, go ahead and give them just a light feeding.   

A midsummer application of organics is beneficial to lily bulbs and is a perfect last minute solution in fall if you have not fertilized at all during spring and summer.  By adding a nice, fluffy one inch layer of manure  (POOpeas™ for instance) or compost around each stem, you are putting the food right where the lilies can access it; natural rainfall or watering dilutes the organics into the soil and takes it directly to the feeder roots where the bulb can utilize the fertilizer.  The basal plate roots under the bulb will take up nutrients as well, but their primary job is to anchor your bulb into the soil.  Basal roots are permanent, but at the end of the growing season stem roots will decompose along with the matured stem and are produced new each year - thus the need for yearly feeding.  

Any guesses as to why the bulblets look pink in this photo but not the first?  They are in fact the same bulbs, but the photo showing the complete stem with green leaves was taken shortly after digging and washing; the other photo was shot late the next day.  The sun caused the color change and is the reason why your lilies can have varying bulb colors even within the same variety.  Lily bulbs on top of the field totes during harvest will take on a slight pink cast, so if you should have two bulbs in a package that are not the same color, it could simply be that one was exposed briefly to sunlight and the other was hidden in the shade.

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