Category Archives: gardening tips

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_leaves
sunburned 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_leaves
yellow 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.

A Walk on the Wildside: The Ongoing Saga of the Hillbilly Gardener

rose_Fourth_of_July
Fourth of July roses

Many years ago I was invited by a Scotts Valley resident to visit their garden. This was no ordinary garden I was to learn during my visit and each spring I look forward to seeing what?s new at Doc Hencke?s garden. From his roots in Oklahoma and Texas he describes himself as the ?Hillbilly Gardener? but with his extensive knowledge of trees, vines and just about anything that grows he is one of the most successful and enthusiastic horticulturists I know. I wore my walking shoes and we started talking about what changes he?s noted in his landscape the past few years of drought coupled with this winter?s rains.

straw_bale_veggie_garden_Ghio_bearded_iris
Straw bale veggie garden with Joe Ghio bearded iris

First stop- the straw bale veggie garden. The soil in this part of the garden is blue hard sub soil so this above-ground method of cultivation has been a real success. Richard told me that when the bales were first put in place a couple years ago he watered them thoroughly to start the fermentation process. Using a meat thermometer he determined by the internal temperature when fermentation was complete. He then soaked the bales with liquid organic fertilizer and applied some blood meal to augment nitrogen. The straw bales are decomposing each year but he?s going to use them once more this season. His crop of kale, lettuces and chard looked robust and happy.

Nearby a bed of Joe Ghio hybrid bearded iris were in full bloom. ?It?s been a great year for iris?, Richard said. Not so good for peach leaf curl. The rains this winter set the perfect stage for the fungus to proliferate. He joked that the birds get the peaches anyway.

Richard is redoing his pond this year. He?s tired of fighting the raccoons and algae. Steeper sides will deter the raccoons and deeper water will help to prevent algae growth. He was forced to remove a curly willow that shed leaves into the pond as their natural salicylic acid was poisoning the pond.

succulent_collection
Succulent collection with blooming kangaroo paw

Last year a new succulent bed was planted along the back of the house and patio. His Sticks on Fire all died over the winter from the cold and rain but the aeonium ?Zwartkop?, echeveria ?Sunburst?, kangaroo paw and various sedums were filling in nicely.

weeping_leptospermum
Weeping leptospermun

Below the patio the golden Mexican marigold and blue Pride of Madeira were in full bloom along with a gorgeous stand of Weeping Leptospermum. ?Magnificent this year, just look at this plant. Can you imagine what it?s going to look like in another 15 years??, he said. Pointing out the visual boundaries he creates with flowering vines growing up into the trees, Richard observed that some are going better than others. Sound familiar in your own garden? Even this expert propagator is sometimes stymied by Mother Nature.

Richard_and_the_giant_ China_Doll
Richard and his giant China Doll tree

I love to hear Doc Hencke?s stories as he shows me around. Stopping at a China Doll houseplant that has now grown into a tree he tells me he thinks it?s one of the tallest specimens ever. His giant bird of paradise flower pod opened last week. I?d never seen their enormous blue, prehistoric-looking flowers before.

Richard?s new desert garden along the driveway is growing in nicely with the aloe plicatilis blooming for the first time. Also the yucca he and his brother dug up inTexas is finally blooming. ?I?ve only waited 52 years for it?, he laughs.

There are so many stories that come with each and every plant in Richard?s collection. It?s always a walk on the wild side.

?Pruning Roses- How, When & Why

 

Mixed rose bouquet
Mixed rose bouquet

In between storms I’m itching to get outside and do something in the garden. It’s too early to cut back the perennials as some frosty nights are sure to come our way between now and mid-March. But it’s just the right time to start pruning the roses. It’s best to prune your roses before they start leafing out or some of their energy will be wasted.

Last year, mine were looking just fine in January, thank you very much, so I thought I’d skip the pruning and removing last year’s leaves. Boy, what a mistake. Oh they looked great in January and February when there was no precipitation. Then some rain fell in March. I’m not kidding when I tell you that every single leaf got black spot and rust. My rose varieties are usually resistant to disease but they could not fight back against the fungal spores lurking in the soil just waiting to colonize those old leaves.

Yellow fragrant rose
Yellow fragrant rose

Roses give so much back I think they are worth the extra mulch and a little extra water to keep them producing those lovely blooms. There’s nothing quite as dramatic as a mixed bouquet of scented roses on the table.

I want my rose bushes to produce lots of roses on a compact shrub and not just a few exhibition size blooms so I prune my shrubs moderately. My goal is to keep the center of the plant open for good air circulation aiming for a vase-shaped bush with an open center. I’ll cut out canes that cross, saving the better of the two, prune spindly and diseased stems and dead wood. I’ll also prune canes that appear weak or broken. Healthy canes appear green or reddish while old and dying canes are brown. Then I’ll cut back the remaining stems by about third. When pruning cut canes at a 45-degree angle just above an outward facing leaf bud or a swelling on the cane. Slant the cut away from the bud to encourage growth outward. Clean pruners afterward to prevent the spread of disease and keep your pruners sharp to make clean cuts.

Same goes for climbing roses. Cut out extra stems if there are too many and also cut back long established canes to the place where they are slightly thicker than a pencil. Then cut each side stem down to several inches. This will cause the cane to flower along its complete length for a beautiful spring display.

Bouquet of mixed roses
Bouquet of mixed roses

Heirlooms roses such as David Austin, other old antique garden roses, and floribunda roses require less pruning because their open look is part of their charm. Keep this in mind and prune lightly. Old garden roses that bloom once in the spring should be pruned after flowering.

I got off easy this year as one of my roses was pruned and de-leafed by a deer who got inside the fence one night but the others are getting pruned the right way and at the right time. I know those old leaves will spread fungus spores and possibly infect the new growth so I’ll patiently pluck them off.  If you have a huge climber this might not be possible and spraying with fungicide may be your only option if you’ve had disease problems in the past. Rake up the debris beneath the plant and discard to eliminate overwintering fungus spores. It?s a good idea to spray the bare plant, coating the trunk, branches and twigs and the surrounding soil with a combination organic horticultural oil to smother overwintering insect eggs and a dormant spray like lime-sulfur or copper soap to kill fungus spores. If you usually only have problems with black spot you can use a mixture of 1 teaspoon baking soda with a few drops of light horticultural oil in 1 quart water and spray every 7 to 10 days during the spring.

Pruning intimidates some gardeners but when you understand the reasons for making the cuts pruning becomes less daunting. The reasons to prune are for health, appearance and to control size.

Prune your roses throughout the growing season, too. Deadheading or cutting off spent flowers encourages plants to re-bloom. Every time you cut a rose bloom to bring it indoors or deadhead a fading rose prune the stem down to shape the plant at the same time. Prune to a spot that has at least 5 leaflets. Roses grow from the point where they are cut so consider the overall shape of the plant as you snip.

Don?t worry whether you?re pruning job is perfect. Roses are super forgiving and you can always trim them up again later. Roses are like redwoods -you can?t kill one- they?re the energizer bunnies of the plant world.