Q. My sago palms (actually cycads)
planted in my yard are turning yellow. Can you tell from this picture what they
need?
 |
| Yellow fronds of sago palm can arise because of its planted location, poor soil used for planting, and watering. |
A. You have three choices about why
the fronds are yellowing: their location (landscape exposure), needed soil
amendments (including fertilizers), and improper watering. It is up to you to
figure which one (or several at the same time) might be responsible.
Judging
from the pushing of new growth from the plants center, I think they are getting
enough water during the week. Water this plant three times a week, not more
often than that. Don’t reduce the weekly amount of water it is getting!
 |
| Notice the artificial grass that was installed. Removal of a lawn and replacing it with nothing that adds to the soil can cause yellowing of fronds due to a slow decline of organic matter in the soil. |
When
you are watering, apply it to a depth of 12 to 18 inches. This will mean that
you need to apply in a single application anywhere from 5 to 8 gallons of
water. Apply this water through three emitters, located 12 inches from its
trunk, to get a good distribution of water. Don’t split the application of
water in the morning and another in the afternoon. That’s silly unless you see
an enormous puddle of water when you irrigate. If water puddles on the soil
surface, split the application of water into two applications an hour or less
apart.
 |
| Rooting depth and how deep to water varies with the size of the plant. Taller plants need deeper (and less frequent) watering. |
This
plant is originally from the richer soils of northern India. It evolved with these
types of soils. It doesn’t like the extremely low organics of desert soils! Iron
fertilizers should be added to the soil in the early spring but now is okay to
do it. Be sure to add this composted soil where the soil gets wet. If the
compost you are adding comes in a bag without a description, then it is
probably low in fertilizers as well. Mix in the appropriate fertilizers to the
compost before mixing it with the soil.
.JPG) |
| Late in the growing season requires spraying iron on the foliage several times about a week apart to be effective. |
Make
sure any surface mulch is at least two inches deep. Using mulch adds one or two
days of extra water! Mulch can be crushed rock or wood chips. Wood chips are
better because they decompose in wet soil adding organics to it as the wood
chips decompose. Crushed rock doesn’t add any organics back to the soil. You
should add organics to the soil (compost) every two years if the mulch is
crushed rock.
 |
| Rock surface mulch adds minerals to the soil as it breaks down, not organics. |
Plants have to handle that.
If
a lawn was removed in the past three to five years this might explain the
yellowing as lawn adds “organics” back to the soil. Removing the lawn also
removes the “organics” added by lawns.
.jpg) |
| Lawns add organics back to the soil from its root growth and lawn clippings left to decompose. |
I
don’t think this cycad will be better in a different location’ but cycads grow
best on the north and east sides of a home. They prefer to grow with morning
sun and afternoon shade.