Barbara Olsen Garden Design . Gardening . Consulting

06/07/2026

04/04/2026

Siberian iris, spuria iris and crested iris are easy-to-grow perennials bloom in spring. Here's expert advice on choosing and growing them.

04/04/2026

All about... manure.

*GARDEN TIP OF THE WEEK*

The Scoop on Manures

Well-rotted manure is great for building soil health and fertility. Unlike commercial fertilizers, it provides a shot of beneficial microorganisms that keep roots healthy, releases small amounts of nutrients over a long period of time, It also improves soil structure.
Another plus is that you can sometimes get manure for little to no cost from a local stable or farm if you pick it up yourself.

The Source Matters
Each animal produces manure with unique characteristics.
• Cow manure is very loose and much of the plant material in it is well digested.
• Poultry manure is rather dry and is high in salts; the use of fresh poultry manure often burns plants.
• Horse manure is dry and contains a lot of undigested plant material, even viable w**d seeds.
• Sheep and goat manure takes the form of hard pellets that are easy to handle and they contain more nutrients per unit volume than cow manure.
• Rabbit manure should be used sparingly since it is very high in nutrients

Caution
• Never use manure from any animal that is carnivorous or omnivorous. Wastes from dogs, cats, or pigs have microorganisms in them that could cause disease in people.

• Even the manure of vegetarian animals can contain disease organisms such as E. coli and Salmonella, so wear gloves when handling fresh manure and allow it to compost or decay thoroughly before using it.

• If you are unsure about whether manure is fully decayed and you want to use it in the garden, don’t use it on root vegetables, or till it into the soil at least four months before harvest.

• If you don’t want to work with fresh manure, you can purchase it already composted in plastic bags. The most commonly available manure is from cows and chickens.

• Too much manure is far worse than a bit less than what you need. Excess manure may burn plants, produce an overabundance of vegetative growth at the expense of fruit or flowers, and may pollute waterways.

For more information, read “The Magic of Manure” in the November/December 2020 issue of The American Gardener, available in the magazine archive on our website.

Photo
Hayden Soloviev, Wikimedia

04/04/2026

Growing Natives Garden Tours!

Growing Natives Garden Tour is a free tour of native gardens in Santa Clara Valley & Peninsula, San Francisco Bay Area, organized by the California Native Plant Society (Santa Clara Valley Chapter) in association with the UC Master Gardeners of Santa Clara County and San Mateo and San Francisco Counties.

April 18 = South Bay Gardens
April 19 = North Bay Gardens

Register to attend here: https://gngt.org/GNGT/register.php

Volunteer to help here: https://gngt.org/GNGT/vol_register.php

Learn more in general here: http://gngt.org

California Native Plant Society - Santa Clara Valley Chapter

04/04/2026

April is California Native Plant Month!

Calycanthus occidentalis, known commonly as Spice Bush or Western Sweetshrub, is a California native shrub that naturally grows in canyons, stream sides and moist places but can thrive in water wise gardens if planted in partial shade with a few deep waterings a month in the dry season. More water is needed in inland locations or if planted in full sun.

The lotus-shaped flowers can resemble a small magnolia flower. The seed pods are interesting looking and the foliage has a spicy fragrance when crushed.

It's also one of UC Davis' Arboretum All Stars. What's an All Star? That's a list of 100 plants that even under difficult conditions will grow well in our area. After narrowing down their favorites to a list, testing them in the Arboretum as well as field trials throughout the state, they picked these 100, hence the name, “Arboretum All-Stars.”

More info:
https://arboretum.ucdavis.edu/plant/western-spice-bush

UC Davis All Star List: https://arboretum.ucdavis.edu/arboretum-all-stars

03/30/2026

Lichens are not a bad thing.

02/20/2026

In this episode of Stories from the Garden, Dr. Allan Armitage explores one of nature’s most hopeful plants: firew**d.

If you’ve ever traveled through areas that have experienced wildfire, you may have noticed something remarkable. Not long after the smoke clears, tall spikes of vibrant pink-purple flowers begin rising from the blackened earth. That plant is firew**d—and its name tells the story.

Listen here: https://www.allanarmitage.net/stories-from-the-garden-podcasts