Design trends

Hardy Geraniums in the Garden

Hardy geraniums are easy to care for and make lovely ground covers.

Last fall my neighbor planted the slope in front of their house with hardy geraniums- lots of them. Over the winter they were looking a bit scraggly and I was worried that maybe they had chosen the wrong ground cover for their situation. But no, come last spring their rich blue geranium ‘Rozanne’ burst into bloom and it’s a site to behold.

Most people use the common name geranium to describe what is actually a pelargonium. Ivy geraniums, Martha Washington pelargoniums and zonal geraniums are all pelargoniums. Hardy geraniums, also called cranesbill, look very different. Leaves are roundish or kidney-shaped and usually lobed or deeply cut. Flower colors include beautiful blue, purple, magenta, pink or white and often completely cover the plant with color. I’ll bet if you visited a garden on a tour or admired a picture in a garden magazine it contained true geraniums. Here are just a few strong performers available among the dozens of species.

Geranium maderense grows best in shade. This dramatic native of Madeira is the largest geranium with huge 1-2 foot long leaves shaped like giant snowflakes. Clusters of thousands of rose tinted flowers form on a 3 foot trunk. This perennial is short-lived but self sows freely. Add some of these architectural plants to your border for color and structure.

Blue flowers in the garden are always a hit as they combine so well with other colors. Geranium Orion‘s abundant clear blue flower clusters bloom over a long season. Use this 2 foot spreading plant in sun or part shade in a mixed border or as a groundcover. There are other blue flowering geraniums. I grow geranium ‘Brookside’ on my own garden. It’s on the second round of blooms. It’s large bright blue flowers are larger than ‘Johnson’s Blue’. ‘Rozanne’ is another common favorite with stunning blue flowers.

Looking for a fast growing variety? Geranium incanum which covers itself spring through fall with rosy violet flowers, fits the bill. Cut back every 2-3 years to keep neat. This variety endures heat and drought better than other types but needs some summer water. It self seed profusely which might be exactly what you want for a groundcover in a problem area.

Geranium Biokova

If pale pink is your color, plant geranium x cantabrigiense ’Biokova’. This excellent groundcover spreads slowly. The numerous one inch flowers are long lasting and cover the plant from late spring to early summer. Their soft pink color is indispensable when tying together stronger colors in the border and the lacy foliage is slightly scented.

Another geranium in the same family is ‘Karmina’. I’ve been growing this dark pink flowering variety for several years. With lush green leaves on a low spreading plant it’s pretty even when not in bloom.

There are a couple other varieties that are popular and deserve a try. They are Award Winning ‘Mavis Simpson’ and ‘Russell Pritchard’. Both have bright pink or purple flowers and make good additions to your perennials.

Give the hardy geranium a place in your garden.

Design trends

Planting Under Trees

Be careful when planting under dogwood

Many of us live under oaks or are surrounded by redwoods. We know the value of trees in the landscape. Trees shade us in the summer. We anticipate their showy blossoms in the spring and enjoy their beautiful colorful foliage in the fall. You can hang a hammock between two of them or tie a rope swing for the kids from a large branch. Trees are our companions, but how can you create a garden under one of them?

Planting under a mature tree can be a challenge. You need to avoid damaging their roots and your new plants will need to cope with dry soil, shade, root competition and ever-changing moisture and light conditions. You want both your new plants and your tree to thrive.

Meet your tree’s needs first. Some trees are more agreeable than others about giving up some of their ground. You can still plant beneath trees that are sensitive to having their roots disturbed but you’ll need to make a few concessions. When purchasing plants to grow under trees, think small. Small plants require a smaller planting hole and this will minimize disturbance to the roots. You may have to buy more plants but you’ll have an easier time tucking them among the roots.

Don’t alter the grade of the soil around a tree or change the soil pH very much. Even adding a layer of soil that is more than 2 inches deep can reduce the amount of moisture and oxygen available to the tree and hinder gas exchange to existing roots, causing trees to suffer or even die.

Only the toughest plants have a chance of surviving among the surface roots of shallow rooted trees. Be careful when disturbing sugar maples, elms. cherries and plums, dogwoods, magnolias, pines and oaks. The majority of a tree roots are small woody roots and fine hair roots that grow within the upper 12-18 inches of soil and extend far beyond the trees drip line. These roots are responsible for absorbing water and nutrients from the soil.

If you encounter a root larger than 1 1/2 – 2 inches in diameter while digging a hole for a plant, move the planting hole a few inches away to avoid slicing through the root. You will sever mats of small tree roots when digging, but they’ll regenerate fairly quickly.

To avoid wounding the bark, which may cause insect and disease problems, start planting at least 12 inches away from the trunk. Oaks shouldn’t have any plantings closer than 6-10 feet from the trunk and those should be drought tolerant. After planting, water to settle the soil and spread 2-3 inches of mulch to conserve moisture and keep weeds down. Be sure to keep mulch at least 12 inches away from the base of the tree. Mulch can hold moisture against a tree’s bark and cause rot and disease.

A Forest Pansy redbud in fall color.

Trees that will tolerate some disturbance to the root zone include Eastern redbuds, both the green-leafed and the purple- leafed species, and red maples which are also a good lawn tree. Common trees that are easy going about plantings underneath are crabapple, ginkgo, hawthorn, honey locust, poplar, silver maple and willows.

So what plants will transform your bare patch of hard earth and knobby roots into a shady nook? If you’re going for a lush look, consider hostas and ferns, paired with the hardy geraniums like Biokova. Other good companions are astilbes with their feathery flower plumes and variegated euonymus fortunei with bergenia or digitalis mertonensis with liriope, lamium, vinca minor, hellebore or brunnera.

Trees with branches limbed high look good with small shrubs planted underneath. Red-leaf barberry can brighten up this spot and also provide fall color. Small nandinas like Harbor Dwarf make a good ground cover and their foliage takes on an orange-red color in winter. Fragrant sarcococca grows well in this situation, too.

Low groundcovers make a simple statement under the crown of a tree. Ajuga, pachysandra and sweet woodruff all grow well here. Or you might like the look of the shade tolerant grass-like plant like carex morrowii ‘Evergold’. This stunning sedge makes a beautiful clump 1-2 feet high and 2-3 feet wide with dark green leaves and a central band of creamy white.

You can have a beautiful garden under a mature tree by following these tips.

Design trends

How & When to Espalier Plants

This local star jasmine has been trained in the formal
Belgian Fence style

Over the years I’ve visited many gardens and been asked for advice on how to deal with a narrow space. We all have ‘em. Sometimes it’s that area between the garage and the fence. Or maybe the neighbor’s deck overlooks your patio but there’s not room to plant a hedge. Or maybe you want to break up your garden with a graceful screen that doesn’t take up too much space. Whether you have an edible in mind that would look great in that space or want an ornamental plant to bring some color, flowers, birds & butterflies, there are lots of choices for shrubs to train as an espalier no matter what your growing conditions are.

I’ve read that the practice of espalier originated in Medieval times when residents of warring cities planted trees inside their walled cities. The Roman and Egyptians are also said to have trained fruit bearing plants like fig, apple, pear and citrus in their gardens but it was the Europeans, specifically the French who perfected the designs we see today.

A nicely trained apple.

Dwarf pear and apple trees are pretty easy to train. Both these trees produce thickened spurs which is where the fruit develops so don’t lop them off when you prune. They are easy to see. You’ll need cat least 6 hours of sun a day for them to produce fruit.

Camellia thrive in shade and because they have flexible branches they lend themselves to training. Pyracantha is also forgiving of mistakes for this reason.

Narrow spaces can be challenging. One of my favorite plants that naturally grows flat is grewia occidentals or Lavender Starflower. it grows fast in sun and attracts hummingbirds and other birds. Beautiful lavender flowers cover the plant from spring to fall.

Another plant, azara microphylla, also grows flat without much coaxing on your part. This small dainty tree is fast growing and reaches 15-25 ft tall. The yellow flower clusters will fill your garden with the scent of white chocolate in late winter. They are ideal between structures. I’ve used the variegated version to screen a shower and it’s working great. The chocolate fragrance of this plant is really what makes it a show stopper.

Flowering quince is an old garden staple providing early color. They are easy to care for and nearly indestructible in almost any soil that is well drained and not overly fertile. Once established quince is a very drought tolerant plant and their spiny branches make them an excellent choice for hedges, screening or as a security barrier. There are red, pink, orange and white flowering varieties. The Toyo Nishiki cultivar even has pink, white and solid red flowers all on the same branch.

Another small tree, the Compact Carolina cherry laurel can be espaliered also in a narrow space if needed. It grows 10 ft tall but that may be all you need to screen the neighbor. They are drought tolerant once established, deer resistant and the perfect host for birds, bees and butterflies. The leaves smell like cherries when crushed which gives this plant it’s common name.

Other ornamental shrubs that make great espaliered plants are abutilon, bougainvillea in frost free areas, callistemon, dodonaea, feijoa, gingko, sarcococca, viburnum, ribes, rhaphiolepis, pittosporum tobira and osmanthus fragrans. Trees that can be trained include cercis, agonis flexuosa, eriobotrya, and podocarps.

California native plants that can be espaliered are garrya, fremontodendron. Carolina cherry, flowering currant and ceanothus while the branches are young and supple.

A young fruit tree in training

Don’t be overwhelmed if an espalier gets out of hand during the season. Just nip the branches back to a leaf node. Use heavy jute to attach the branch to the support wire or stake. After a season the jute will rot away which keeps the branch from being girdled by the restraint.

Design trends

Marigolds & Fruit Trees in the August Garden

Marigold are valuable in the garden but not for aphids.

I’m more into drinking ice tea and reading a good book on my Kindle than I am motivated to remove errant blackberry vines or control the hypericum creep. And certainly it’s more fun to plant a new addition in my garden than deal with the spider mites. Guess the Dog Days of summer are upon me and there’s still a lot of August left to go. You know the old adage: Do as I say, not as I do. Well, listen up.

Here’s some advice for those of you growing fruit trees. August is the best time to do summer pruning. If you haven’t already done so, thin out shoots and crossing branches. This allows more air and light into the tree, reduces disease and promotes earlier ripening of the fruit. Remove most water sprouts. These are the soft, fast growing shoots usually growing straight up. Cut them back to a main branch. If you need to fill in a spot in the tree and there’s a water sprout growing there, cut that one back to about 2 inches to promote a fruiting spur.

This Red Delicious tree could use some thinning and a little trimming.

Pruning fruit trees this month controls the size of the tree and can also prevent rampant sprout growth next spring. That’s because pruning removes many of the little food factories (leaves) that supply energy to the plant and store it, to be used for growth in the spring.

Prune to maintain a vase shape. By promoting upright limbs high in the tree and pruning hardest in upper and outer portions, fruiting wood is maintained throughout the tree. Also eliminate limbs growing inward. Remember never to prune more that 1/4 of the total mass of your tree at any one time and no more than 1/3 per year. Better to space out corrective pruning over 4 years if your tree has gone too long since the last pruning.

One last thing, fertilize your trees one more time. Most established fruit trees need their first application when the tree begins to emerge from dormancy in the spring, another after fruit set and the third immediately after harvest. For young trees in the first, second or third growing season, apply at half the rate. Feed your trees and they’ll feed you.

The other day at a garden center I was admiring the huge selection of marigolds. So many kinds and colors are available these days. All marigold are native to subtropical America and have been cultivated in Mexico for over 2000 years. But do they really help with pest control?

Like other members of the daisy family, marigolds provide nectar to beneficial insects, such as syrphid flies, who prey on aphids and other insects that attack garden plants. Parsley and dill flowers are even better but daisy family flowers keep the nectar flowing longer.

The USDA lists a total of 15 pests that attack marigolds. Included on their list are aphids, Japanese beetles, snails and spider mites. So they are effective in luring these pests away from your other ornamental plants.

Marigold have been shown to have some slight effect in repelling cabbage worms and bean beetle larvae. A variety called Stinking Roger repels flies that bother cows and other domestic animals but I’ve never seen this marigold available around here.

The common French marigold that has been shown to control nematodes. You need to plant them thickly as a cover crop and allow them to grow for many weeks to be truly effective.

So now you have the rest of the story. The bottom line, plant marigolds as they do have some beneficial effects but mostly because they’re pretty.

Design trends

Poisonous Plants in the Garden

Hydrangeas contain cyanide

When you look at the list of plants that are toxic in one way or another to humans or pets, it’s a wonder any of us has survived. Maybe it goes under the same category as drinking out of a garden hose when you were young but poisonous plants are a more serious threat. Take a look at your garden and evaluate the risks of these common plants if you have pets or small children.

Not that long ago I was suggesting vines for a design I was working on. The client had a dog that nibbled plants so I wanted to make sure none were toxic. Of the common vines I suggested that do well in our area Bower Vine, Royal Trumpet Vine, Goldflame Honeysuckle and Lavender Trumpet Vine were eliminated from our consideration.

Many of us are including native plants in our landscapes to attract wildlife and save water and resources. Here are some common native plants that you should be aware of if you have small children. This list comes from
Borstein, Foss and O’Brian- California Native plants for the Garden.

Coffeeberry- leaves, berries and bark
California buckeye- all parts (poisonous to bees also)
Western azalea- all parts
Elderberry- all parts except ripe berries and fruit
Solanum-all parts
Snowberry-berries
California buttercup- juice of the plant
Berberis- roots and leaves
Prunus ( cherry )- seeds
California poppy- all parts
Lupine (annual)- seeds, fresh leaves and stems.

Beware the lovely rhododendron

Rhododendrons are just one or our beautiful plants that are poisonous. Children are more susceptible to the effects of plant toxins and should be taught not to eat seeds, berries or leaves from any plant. Do not assume a plant is nontoxic because birds or wildlife can consume it without harmful effects. Be prepared for an emergency by keeping syrup of ipecac on hand and the number of the Poison Control Center. ( 1-800-222-1222 )

Small pets can also be at risk if they ingest parts of poisonous plants out in the yard. Know what plants you have and keep a list. Oleander and foxglove are notorious deadly plants. Here are just some others you might not know.

Hydrangea leaves, flowers and branches contain cyanide. Lantana foliage and especially unripe berries also contain dangerous toxins while delphinium leaves and seeds contain toxic alkaloids which decrease as the plant ages. Sweet peas, lobelia, impatiens, carnations, calla lily, mums and bleeding hearts also have plant parts with come degree of negative effect if ingested.

Surprisingly, even some vegetables contain natural toxins. Diseased celery and green potatoes as well as potato leaves and sprouts produce a very strong toxin. Raw, green, young asparagus shoots can cause dermatitis and the red berries that form on their feathery branches are poisonous. Large quantities of tomato leaves and stems contain alkaloid poisons. Livestock have died from eating the foliage. I guess the deer that browse your tomato vines aren’t ingesting enough to cause them harm as they seem to know just when you have another set of buds for them to nibble.

Trees are not the most common cause of accidental poisonings around the home but a few species may present a hazard.

The black seed inside apples contain cyanide although you have to eat large quantities for them to be deadly. Peach kernals, bark and twigs contain cyanide also as do apricot, cherry and plum pits.

You don’t have to eliminate plants around the home that have natural toxins. Humans have lived for centuries around gardens and orchards. Just be prepared by knowing what plants grow on your property.

Design trends

Planting Tips for Containers

Native Western Azalea is a sure “thriller” in any container

I used to have over 300 containers. Then I whittled them down to 200. The fire took care of that but I saved a bunch by cutting away burned roots, replacing melted pots and giving the survivors some TLC. I consider them pets now given all the care I have given them over the past two years. Now that they are showing progress I have my eye on planting new containers with natives, succulents and more flowers for the butterflies. I might try my hand at container vegetables again although last year’s effort was not very successful given the amount of shade that I have. Every gardener has their your own trial and tribulations, too, so I’ll quit whining now.

Adding California natives to my collection of container plants has been a goal for a long time. Besides attracting birds and wildlife to the garden they use less water than most container plants plus they are beautiful. Gardening in containers is easy. You can control the soil, water and light and the gophers can’t undermine your efforts. There are a lot of California native plants that do well in containers and I’m going to place them where both the birds and I can enjoy them.

This Woodwardia is growing in the ground but they also do great in containers

Natives that will do well in part shade include Western Azalea (Rhododendron occidentale), Chaparral Pea, Giant Chain Fern (woodwardia) and Deer grass. These plants grow big and are best for large containers. You can visit CalScape website for more native plants for any exposure and tailored to your exact location. https://calscape.org/search/

Dramatic containers utilize the concept of combining a thriller, some fillers and spiller or two. Not all my containers will use this formula but I seem to be drawn to those that do. Plants in nature can be quite random in the way they grow together and still be lovely. Containers need a bit more order to dazzle and direct the eye.

Thrillers act as the centerpiece of a container. They are usually big, bold and beautiful. Giant Elk Clover is one such California native that is an attention getter. It grows in part shade. Others that need more sun include Chilopsis linearis (Desert Willow) is another great subject for containers as it is slow growing and beautiful in leaf and flower. Other architectural natives that will catch your eye as the centerpiece of a container are Hardy Hibiscus (Rose Mallow) and Pacific Dogwood. The thriller goes in the center of the pot or if your container will be viewed from only one side it goes in the back.

Next come the fillers. They can be foliage or flowering plants but they should complement and not overwhelm your largest plant. Usually they have a mounding shape and I’ll plant several around the thriller. Good fillers include Heuchera maxima and Western Maidenhair fern, both which like part shade. Lucky for me.

The last plants I’ll add are the spillers which are small and will soften the edge of the container. Redwood Sorrel, Wild Ginger and Miner’s Lettuce are good choices. California Fuchsia would look spectacular with its red or orange flowers and grey foliage spilling down the side of my container if I had more sun.

In choosing a container, remember a porous clay pot will dry out fast in the summer sun as will a small pot. If you want pots on a sunny deck, you’ll have better results if your container is made or ceramic or colored plastic and is big enough to allow 2 inches of potting soil around the root ball. I don’t use water absorbing polymer granules in my containers as they are all in shade in winter and would stay too wet depriving plant roots of oxygen.

Water when the top inch or two of soil is dry depending on the size of the container.. On a very hot day, watering mid-day will cool the soil although I like to get my watering done early. Get to know your plants. Plants that are still growing into their containers need less frequent watering than those that are getting root bound. How much water? Water until it runs out the bottom and empty the saucer the next day if any water remains. Use a gentle nozzle that doesn’t dislodge the soil or compact it. Also make sure the water in the hose isn’t hot from lying in the sun.

The best overall soil mix for natives in containers is sharp sand and horticultural pumice added to a good potting soil. Never use perlite or that puffed up pumice because it will float and look terrible Don’t add gravel or clay shards at the bottom of the pot as this impedes drainage. It work best to fill the entire pot with soil, top to bottom with a screen over the hole to keep out earwigs and sowbugs.

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