Category Archives: citrus trees

Troubleshooting Plant Problems

Troubleshooting is a form of problem solving. And whether it’s a car problem, your smart phone, an irrigation system or yellowing leaves on a plant the goal is to solve it and make the product or process operational again. When you eliminate the potential causes of the problem hopefully the solution restores everything to its working order. Sounds like something Sherlock Holmes would say and it’s sometimes easier said than done as we all have experienced.

burned_heuchera_leavessunburned heauchera leaves

A few weeks ago I received a text with pictures of some plants with brown spots and asked what I thought might be the problem with their plants. This was after the heat wave we experienced and after asking a few questions about irrigation, location and how long the plants had been in the ground, I determined that the plant leaves had been burned in a pattern consistent with the location of the beating sun. At this time of year plants are growing wildly and need a good soak moistening the entire root zone. The solution: Better to water deeply less often than lightly which might not reach all the roots.

The subject of how much fertilizer and what kind came up in another troubleshooting email thread between some fellow horticulturalists. The issue was whether to use another round of organic high phosphate fertilizer in order to encourage bud development on a notoriously short-season tree dahlia. After some lively discussion we decided that the early spring application of rock phosphate was sufficient. Sometimes adding too much phosphorus may actually hurt a plant by preventing the uptake of other nutrients which must also be available to the plant in order to prevent unexpected deficiencies to appear. A balanced fertilizer containing all three nutrients- nitrogen, phosphorus and potassium-was recommended for the remainder of the season.

yellow_lemon_leavesyellow leaves on lemon

Then there were some problems in my own garden. Well, it seems I am always trying to solve something with plants, pests or critters but this was with my lemon tree. At first I was perplexed when the older leaves of my lemon tree started turning yellow a couple months ago. The new growth looked fine so it wasn’t an iron deficiency where the young leaves display green veins along with the yellowish color.

It wasn’t a nitrogen deficiency either where the mature leaves slowly bleach to a mottled irregular green and yellow pattern, become entirely yellow and then are shed while the discoloration spreads to the younger leaves. I had fertilized in March with an all-purpose balanced fertilizer. Citrus are heavy feeders and require a steady source of nitrogen, the ideal citrus fertilizer having a ration of 3:1:1 (N:P:K)

After eliminating other mineral deficiencies or overwatering as the problem I decided that my lemon was simply dropping interior leaves which is normal after winter but I wanted to trouble shoot all potential causes to be sure citrus greening wasn’t the culprit. If it had been this deadly disease the leaves would have exhibited an asymmetrical pattern.

To quote Sherlock Holmes “Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth.” I’ll try to remember that when I’m troubleshooting my next problem in the garden.

Man’s Best Friend Detects Deadly Citrus Disease

The author and Sherman, a Welsh Springer Spaniel, at the Bonny Doon Ecological Reserve. Photo by Tom TrowerThe author and Sherman, a Welsh Springer Spaniel, at the Bonny Doon Ecological Reserve. Photo by Tom Trower

If you have a pet dog it’s no secret that they are always happy to see you. Dogs provide us with companionship. They love us unconditionally and never seem to have a bad day. Their ability to read human gestures is remarkable. Even our closest relatives- chimpanzees and bonobos- can’t read our gestures as readily as dogs can. They pay attention to us as human infants do. This accounts for the extraordinary communication we have with our dogs. Some dogs are so attune to their owners that they can read a gesture as subtle as a change in eye direction.

Another picture of Sherman ‘cuz he’s just so cute. Dressed up for the Fourth of July.Another picture of Sherman ‘cuz he’s just so cute. Dressed up for the Fourth of July.

 

Studies have shown that dogs were the first animal that humans started keeping as pets. No one can pinpoint the exact date, but estimates range from roughly 13,000 to 30,000 years ago. Archaeologists can tell domesticated canines apart from wolves through skeletal differences. The earliest dog bones, discovered in Belgium in 2008 are from 31,700 years ago. Ancient dog skeletons have also been unearthed near Ukraine and elsewhere across Europe, Asia and Australia, suggesting that canine domestication was a widespread phenomenon.

How did dogs become domesticated in the first place? The first ones were basically just tame wolves. Instead of the survival of the leanest and meanest wolf it came down to survival of the friendliest around the garbage pile at the edge of human settlements. Aggressive wolves would have been killed by the humans. Friendliness caused strange things to happen in the wolves. They started to look different. They no longer needed strong jaws and sharp teeth. Their noses got smaller, their ears floppy and they evolved the ability to read human gestures.

Fast forward to 2016 when the California Dept of Food and Agriculture reported in their ‘Food and Farming News’ that dogs are being enlisted to help protect citrus trees. Mary Palm, the USDA Animal and Plant Health Inspection Service (APHIS) national coordinator for the citrus pest program, said dogs have been successfully trained to detect canker disease and now Huanglongbing or greening disease in citrus.

Espalier lemonEspalier lemon

Huanglongbing or greening disease (HLB) is a deadly bacterial disease that has decimated the citrus industry across the world. The USDA has already spent hundreds of millions of dollars looking for a cure. In California, nearly one-third of the state’s entire land mass or 21 counties are in quarantine for the bug- the Asian citrus psyllid- that can spread the disease HLB in citrus groves. The quarantine requires that fruit moved from those areas be free of leaves and stems and movement is restricted of any nursery stock that isn’t grown in a USDA-approved facility. In addition to many Southern and Central California counties, San Fransisco, Alameda, San Luis Obispo, San Mateo and Santa Clara counties are also under quarantine.

Dogs have long been known to be able to use their senses to detect things that humans require extensive technology to detect. “Over the past four to five years,” Palm said, “a researcher in Florida first determined dogs could actually detect citrus canker. They were very good at it.” Through research funded by USDA, there are now five dogs trained and tested daily to detect huanglongbing disease. Palm said in the next year or two certification criteria will be in place for other companies to train dogs and certify them as detectors. The dogs in this program have a 99 percent success rate at detecting HLB disease in blind studies.

So when you’re petting man’s best friend tonight appreciate all the great things he does for you and for our planet. What would the world be like without lemons and oranges?

Fall Garden to-do’s for the Santa Cruz Mountains

Warm days, rainy days, short days, cold days- all in the fall of the year here in the Santa Cruz mountains. It's part of what makes our area so special to us. We are inspired by Mother Nature and our mountains. We feel a connection with nature as we enjoy our gardens. There are some easy things you can do at this time of year to extend that enjoyment. Gardening should be fun, too.

Taking cuttings of shrubs is a relatively easy and economical way to make new plants. Some plants that can be increased by hardwood cuttings include manzanita, coffeeberry, crape myrtle, pittosporum, euonymous, forsythia, spirea, viburnum and roses.  Edible plants like currants, figs, grapes and quinces also make good subjects.  

For deciduous plants it's best to take cuttings soon after the shrub drops leaves and the plant goes dormant. Evergreen shrub cuttings can be taken now. Start by taking cuttings of year old wood that's about a quarter inch in diameter.  Discard the top couple of inches of each stem since this unripened wood doesn't have enough stored nutrients to survive.  Cut the stems into 6-9 inch pieces.  Because a cutting won't grow if planted upside down, make the top cut at a slant, so you can keep track of it.  Then dip the bottom ends in rooting hormone and tap off any excess.  

You can store cuttings from dormant shrubs bundled and labeled in boxes of sand in the garage or outdoors in a well-drained trench. Each will form a callus at the base where roots will form next spring.  Come spring , plant the cuttings in good soil in shade with only the top bud exposed. Water as needed and once the new plants develop leaves and increase in size, start feeding them monthly with a balanced fertilizer. By next fall your new shrubs should be well established and ready to be moved to their permanent place in the landscape.

Some plants like abelia and spice bush are propagated by softwood cuttings in June. You can check the UC Davis website http://rooting,ucdavis.edu for information on specific plants you might be interested in.

Also you can simply pin down a stem of a plant like manzanita by putting a rock on it so the soil makes contact. After a year or so you will have a new plant that you can dig up and move.  Other natives like ceanothus can be propagated in a peat and grit mix and will root in about 50 days if given bottom heat. Take these cuttings in January.

Stake trees.  Trunks with leaning tops or those planted in very windy areas need support.  To determine how high to place ties, move your hand up the trunk until the treetops straightens.  I usually allow the stake to reach up into the canopy a bit so that a wind gust doesn't snap off the trunk right at the base of the canopy.  Tie the tree to the stake loosely in several places.  Trees in containers are tied tightly to the the stake but those in the ground should have some wiggle room to stimulate the trunk to be stronger.  This is a good time to check existing tree stakes to make sure the ties aren't digging into the trunk and the stakes are large enough to support your tree. Remember to keep your tree staked only as long as needed and then remove the supports.

Hummingbirds still need a nectar source.  Don't take down your feeder in the fall.  Anna's hummingbirds live and breed in this area all year long.  They need your nectar more in the winter, when very little is in bloom.  Even a species like the Rufous benefits from access to a large nectar supply to stock up on before a long migration.   Keep your feeders up year-round and keep them clean.  

The recent rains will allow weed seeds to sprout which is just what you want if you're planning a wildflower meadow.  The most common mistake when planting wildflower seeds is not getting rid of the existing weed and grass seeds that are in the soil and will germinate along with the wildflowers. These fast-growing weeds smother the slower growing wildflowers. Take time to eliminate the competition. Get rid of existing weeds when they sprout by cultivating the soil to a depth of not more than 1 inch. Deeper cultivation exposes more weed seeds that will germinate along with the wildflower seeds.

Pick last roses and add alfalfa meal or pellets which will soak into ground and prepare them for next spring. Don't prune until the end of January.
 
Groom strawberries and mulch to deter slugs in winter.

To help protect citrus from frost damage, pull mulch back from below the canopy.  This allows the ground to absorb heat during the day and release it at night.  
 

Citrus & Avocado for the Santa Cruz mts

Late September and you can feel autumn in the air. While our days are still beautiful and warm, nights are getting cooler with less daylight hours. Perfect weather for transplanting or adding new plants to your garden.

Why is this a good time? Cooler air is kinder to plant foliage and soil temperatures are still warm, which creates an excellent environment for new root growth. In the fall many plants and trees ( even broadleaf evergreens ) are entering a period of dormancy. With no need to allocate resources into foliage, plants are transferring all their energy into roots and storing nutrients for the cool months ahead. By spring, the roots system should be well established.

So take advantage of fall planting weather. Decide what changes or additions you want to make in your garden.
Perhaps it’s time to remove lawn from banks or slopes where water runs off instead of soaking in. Replant with more drought tolerant ornamental grasses or perennials.  Picture hummingbirds feeding on beautiful variegated autumn sage, their creamy white and green leaves topped with brilliant red flowers from summer until frost.

If you have a small lawn on flat land and want to improve water absorption and reduce water waste, rake out the thatch that accumulates at the base. Then aerated your lawn in a hollow-tine aerator or power aerator from a rental yard.  This brings plugs of soil to the surface, then rake compost over the hoes and water well.

Now is a good time to plant citrus and avocado. They will fair better during the cold winter months if roots are established.  Remember to give older citrus a good soak every week or so or the fruit will be dry.

If you’ve always wanted an avocado tree there are several varieties that do well here.  The Bacon avocado is hardy to 24 degrees. You can harvest medium sized fruit from November-March. They even produce at a young age and grow to 30 feet tall. Fuerte avocado have excellent flavor. This tree is large and spreading, hardy to 28 degrees and the fruit ripens from November-June. Zutano is another good variety for this area. Mexicola varieties are also very good.
 
These avocados are self fertile for the home gardener. You can expect your tree to live for about which is a lot of guacamole.

If you receive frost of consecutive night during the winter you can easily protect a young avocado or citrus by erecting a simple frame of 1×1" stakes that extends above the height of your tree.  Then drape with a frost blanket or beach blanket on cold night. Don’t use plastic- the cold will go right through it.

Take advantage of this great fall planting weather. Bon appetit !

Citrus in the Garden

There’s always so much to do in the garden in early spring.  It can be overwhelming deciding what’s important and what can wait. This is how I tackle my garden to spruce things up in a hurry.

First, I decide what problems stand out and choose what to do based on which areas will be the most noticeable. Which improvements will have the most impact?

Focus your attention where family and friends gather- the patio, a shady spot if it’s hot or a sunny area if it’s cool in your garden. Clean up what catches your eye like dead limbs, tall weeds or clutter. Sweeping the deck or patio will make the whole garden look better.

Flowers attract the most attention. Focus on the beds closest to gathering spots and those places you see outside the windows.  Enhance what you have. Blooming or bright foliage plants can fill in gaps in beds.

Perk up your entry with new plants. Group several containers filled with plants you love.  The bigger the plant you use, the more immediate the effect. Combine shades of all one color like blue, purple or red for a more dramatic look.

What else can you do to spice up your landscape?  Plant a dwarf citrus. They grow to only 8 feet so fit into small spaces. Plant in a spot that gets full sun and has well drained soil. Citrus are slow growing and do great in containers, too.

A favorite lemon variety is Improved Meyer. It a actually a cross between a lemon and an orange and tastes slightly sweeter than a true lemon  such as the Eureka. The fruit is very juicy and holds well on the tree, increasing the sweetness.

If your’e looking for an ornamental specimen for a patio container, consider a Nagami kumquat. Small reddish-orange fruit hang on the tree nearly year round and you eat them whole-peel and all. This small symmetrical tree is Japan’s most popular kumquat.

Another very attractive citrus is the which is also known as the Clementine. Its weeping form, dense, dark foliage and fruit that is held toward the outside make this a very showy specimen either in a container or in the ground. Sweet and juicy fruit hold on the tree for several months. This is the variety you see in the market from December to May. Wouldn’t  it be great to have one in your garden?