Leaves dropping on Transplanted Tree

Q. Two weeks ago we planted two 5-6″ caliper, 14′ Thundercloud Plums. We dug very wide holes, dug as deep as the root ball, cut off all the burlap, refilled the dirt with 1/3 organic compost to 2/3 original soil, stamped and watered down the replacement soil, and covered with 3″ bark mulch. Two weeks later both trees are dropping leaves. We thoroughly watered them the first week and now water them every two days. Are they suffering from shock? What are your thoughts of the next step I can take to get them healthy? SMRussell – Bothell, WA

A. Dropping leaves is how trees cope with stress. Many tropical trees drop leaves for the dry season and temperate zone trees for winter.   Mid summer is always a tough time to transplant large trees. When possible plant them in the spring or fall.  There are many stress that can cause the leaves to drop as the fine hairlike root structures responsible for water uptake are often damaged. Trees compensate by dropping leaves thereby reducing water loss from the leaves (evapo-transpiration).    Loss of leaves does not mean the plants will die though.  One concern is to make sure you do not over water.  If you have not done so make sure your soil is well draining. If you dig a hole for a tree in a very clay soil it can become like a container that fills up with water and then rots the roots.  Of course rotting roots have the same symptoms as dry roots because the plant can’t take up enough water.  Do a perc (short for percolation) test.  Here is how: http://www.horticultureguy.com/television-segments/testing-soil-drainage/

If your soil is not well draining make sure you test it for moisture before re-watering.  Also for future reference current tree planting does not recommend amending the fill soil.  It is now believed that this may encourage the roots to stay inside the dug area and not move readily into the surrounding soil. – HG

Posted in Gardening Q & A, Northwest U.S. Gardeners | Leave a comment

Fruit Tree Pollination

Q. In one of your answers: Shinseiki Asian pear is “considered nearly completely self pollinated” Does it mean there is no need another pollinator? Lisa- from New York

A.  A little background – most fruit trees have a built in mechanism to prevent self fertilization – presumably because self fertilization similar to inbreeding reduces the vigor of future offspring and limits their gene pool.  This mechanism is not completely on or off but varies. So for example one tree may self pollinate 80% of the time and would be considered “nearly completely self pollinating”.  Another may only self pollinate 20% of the time and would be listed as requiring a suitable pollinator.  You may improve the “nearly completely” pollination with a suitable plant (usually shown on a pollination chart) and presumably get close to the additional 20% pollination.  The pollination chart takes into account the time of bloom (since bees don’t as a general rule pollinate with long term storage pollen) and how closely related the plants are.  Usually if trees share parents the self fertilization prevention mechanism can reduce pollination.  To answer your question – yes you do not require an additional tree for pollination – although pollination could be improved.  If you find that you need to thin fruit each year anyway I would say you do not need an additional pollinator tree.

Posted in Gardening Q & A, Midwest U.S. Gardeners, Northeast U.S. Gardeners, Northwest U.S. Gardeners, Outside U.S. Gardeners, Southeast U.S. Gardeners, Southwest U.S. Gardeners | Leave a comment

Yellow Cucumbers

Q. Why won’t my cucumbers turn green. I have huge yellow cucumbers. Are they edible? thank you, Kathy M. , Illinois

 A.  There are two possibilities here.   If they start out green and then turn yellow you waited too long to harvest and the cucumbers are over ripe. Pick them earlier.  The seeds will be smaller and the fruit will be less bitter. If they are never green and always yellow then you may have been slipped a yellow cucumber variety (or this variety was nearby in the field and crossed in at the source).  These varieties (like Lemon) produce yellow skins.  In addition there are is an outside chance they have a virus which prevents chlorophyll (green pigment) from forming in the skin of the fruit.  Overwatering has been said to cause this but usually you see some problems with the plant itself which you did not mention.  Since you did mention they were very large it is likely that you have the first scenario.  Edible yes…pallatable.. not so much.

Live Long & Garden,

Peter (AKA Horticulture Guy)

Posted in Midwest U.S. Gardeners | Leave a comment

Mulching with Weeds

Q. Your web site is very informative and inspiring. I try to follow your advice as much as I can.  We had good year so far..specially in green house..lots of cabbage, cauliflower,  salad, lots of peas and lots of tomatoes are coming…My question is I have lots of weeds in my garden.. what I used to do is to collect all weeds and mulch it with my lawn mower and mulcher.. and put it back into garden..Now I think I am putting back the weed seeds as well.. how I can prevent those seeds from growing.. or how to kill the seeds naturally before I put em back again..?

Thanks again… ~Vik ,Snohomish, WA

A. To kill the seeds naturally you will need to compost the weeds.  There are two ways that you can compost – low and slow (sounds like Ramone the Chevy Impala on the movie Cars – my son is an avid fan)  or high and fast.  Low and slow means low temperature and maybe a year to process the compost.  This will not remove the weed seeds or bits that may resprout.  You want high temperature (hot) which produces a final composted product in a month or so.  This is the process they use at the LRI landfill (Pierce County Recycling, Composting, & Disposal) where all the yardwaste is processed.  Low and slow is much easier as you just pile up your garden debris and turn it a few times – low key.  To get it to go to high temperatures (120°F–150°F) you have to monitor the types of waste you put in (balance of green or nitrogen rich products and brown – containing carbon like wood chips or brown leaves).  You also have to turn it regularly because the microorganisms that produce heat need oxygen. These temperatures will kill weed seeds and other structures that allow the weeds to reproduce  Rather than go into any more detail here I will refer you to a WSU extension booklet which you can download on composting.

Live Long & Garden

Peter – HG

Posted in Northwest U.S. Gardeners | Leave a comment

Rhododendron Yellowing Redux

Q. I have 2 rhodies that both have leaves that are looking chlorotic with leaves that are yellowing between the veins. I have fertilized like I should, I have bark mulch on them and they still dont have the dark green they should. I did do a soil test with a PH tester and it says its too alkaline but I have no idea what I can do to get the soil more acidic. We have been having above normal rain and have been running 11 degrees below normal temps with temps only getting into the low 50′s.

Can you offer any suggestions on why the rhodies are doing this, is it because the temps are below normal with little sun so far this year? I have read that coffee grounds can be good at increasing soil acidity but how much and how often? Also Im confused on peat moss, some say it doesnt help, others say it does. We ony have access to store bought peat moss, would it help mixing it with compost and applying that?

Thanks in advance for any help. Sandra in Juneau, Alaska

A.  This is a common issue called “interveinal chlorosis” in horticulture parlance (the spell checker doesn’t even recognize those words!). You are on the right track as it is a deficiency of iron and/or manganese (most often iron) and low pH can make these nutrients (called micronutrients as they are needed in smaller quantities than Nitrogen, Phosphorus and Potassium (Potash)).  As I have mentioned in prior posts coffee grounds are great for organic matter but don’t alter the pH of the soil enough to make a difference (the actual coffee you drink would do much more).  So you have two options. The first short term solution is to apply a special type of fertilizer that protects nutrients from the effect of high soil pH (through a process of chelating the minerals) like Miracle Grow’s MirAcid.  This does not change the soil pH but rather delivers the necessary nutrients in a protected formulation.  The long term solution is to drop the pH of the soil using a soil acidifier – which is usually made up of elemental Sulfur.  Follow directions and bring your pH down to pH 5.5.  That should free up iron and manganese if they are present in the soil of course (they usually are since the plant requirements are so low).

Excessive Rainfall can leach out nutrients like iron and low soil temperatures can slow down microbial activity which is essential to the breakdown or organic nutrients.  But I would still get you pH down and then see if this solves your problem.  I would start with the miracid or similar product that has chelated micronutrients to get them greened up quickly and also lower the pH.

Live long & Garden!

Posted in Northwest U.S. Gardeners | Leave a comment