All posts by Jan Nelson

I am a landscape designer and consultant in the Santa Cruz mountains in California. I write a weekly gardening column for the Press Banner newspaper. I am also a Calif. Advanced Certified Nursery Professional and managed The Plantworks Nursery in Ben Lomond, Ca. for 20 years.
Design trends

Living with Houseplants

Houseplants like Peace Lily clean the air of pollutants in your home.

I’m embarrassed to confess that I don’t always take my own advice. Take my houseplants, for instance. Decades of research have shown that houseplants reduce stress and anxiety. They can sharpen our attention, make us more productive and give us a happier outlook. They can fight indoor pollution and add moisture to the air in our homes. So why do a few of mine look so sad?

First a typical house plants lives in the understory of a tropical rain forest where it gets bright filtered light. They’re used to warm rain and perfect drainage. I’ve moved mine to the best light I have but it’s not enough for a few of them. I might have to find them better homes.

I also had a problem last year by fertilizing a little too much. I could see the edges of some leaves were brown which was probably from over fertilizing but also could have been lack of light or too much water. Skip fertilizer in December and January and start up half strength mid-February.

Water just enough to keep the soil from going totally dry allowing oxygen to move back into the root zone. Houseplants are resting at this time of year and don’t use as much water as when they are actively growing. Let the soil in a 4-6 inch pot dry half an inch down between watering then water with room temperature water. And don’t let the pot sit in a saucer of water or the roots will rot. If your plants is in a larger pot let the soil dry down a couple inches.

Don’t re-pot a plant in winter when they are slow to grow new roots. I’m really anxious to transplant a couple of mine into more decorative pots but I’m going to hold off until March.

Plants that I have had good results with in lower light are philodendron, peace lily, Chinese evergreen, cast-iron plant, schefflera, arboricola, ferns and palms. Hanging plants that grow well in low light are hear-shaped philodendron, pathos and grape ivy. Most of these house plants grow naturally in low light areas of the jungle. Don’t overwater and they’ll be happy.

So far, this winter hasn’t been as rainy as last but still it’s been cold and my home is closed up to keep the heating bill down. Without doors and windows open to circulate fresh air, toxins such as benzene, formaldehyde and trichloroethylene can be realized from furniture upholstery, carpets, cleaning products, paint, plastics and rubber can build up inside. Carbon monoxide from the incomplete burning or wood and vehicle exhaust can also be present in indoor air.

Biological pollutants include bacteria, viruses, animal dander, house dust, pollen and dried cat saliva. What? Cat saliva? Do you hear that Archer? House mites, the source of one of the most powerful biological allergens, grow in damp warm environments. Mold and mildew grow in moist places like central heating systems and are just one more source of indoor pollution.

NASA researchers suggest that the most efficient air cleaning occurs with at least one houseplants per 100 square feet. Even the microorganisms in potting soil removes some toxins.

Some of the easiest houseplants to grow are some of the best to have in your home. Any of the plants listed above would fit the bill. If you have a cat or dog that nibbles, however, it’s best to stick with spider plants, palms and orchids, African violets, aluminum plant, bromeliads, peperomia, cast iron plants, Christmas cactus, chenille plant, creeping Charlie, false aralia wandering jew, piggy back plant and succulents like donkey’s tail and echeveria.

With a little planning you can clean the air in your home while keeping the pets safe.

Design trends

Flowers Adapt to a Changing Climate

These cultivated violas look similar to the field pansy in the study.

On this rainy day I’m picturing my garden and deck this summer filled with colorful flowers. The bumblebees will be happy, the hummingbirds will be happy, I’ll be happy. Or will I?

I recently read about a study in France that suggests that humans are quickly altering the way flowers are reproducing and it’s happening in just 20 generations. Toxic pesticides and vanishing habitats have driven down the populations of bees and other pollinators so some flowers have evolved to fertilize their own seeds more often than the seeds of other plants.

Bumblebee populations have declined and it may be that the field pansy flowers in the study are investing their energy into using their own pollen to fertilize their own seeds more, rather than produce big flowers that lure pollinators.

The researcher in the study, Dr. Cheptou an evolutionary ecologist at the University of Montpellier, was inspired to carry out the study when it became clear that bees and other pollinators were in drastic decline. How would flowers adapt? Would they find another way to reproduce?

The field pansies have always been able to reproduce using both methods. But a selfing flower can use only its own genes to produce new seeds. Sexual reproduction allows flowers to mix their DNA, creating new combinations that make them better prepared for diseases, drought and other challenges that future generations may face.

Tracking the evolution of the field pansy was made possible by the cache of seeds from the National Botanical Conservatory in France collected in the 1990s and early 2000s.

The researchers compared these old flowers with the new ones found in the countryside. After growing the new and old seeds side by side in the lab under identical conditions, they discovered that selfing had increased 27 percent since the 1990s.

Other changes of note were that although the new field pansies had not changed in their overall size, their flowers had shrunk by 10 percent and produced 20 percent less nectar.

So this change in reproduction may be making a bad situation worse for pollinating insects. The genetic limitation of selfing could put plants at risk of extinction.

Flowering plants are dealing with other issues such as global warming which speeds up the growth of the flowers and shrinks the window of time before the flower wilts and has nectar for pollinators.

Another study, however, on morning glories in the southern United States, found that between 2003 and 2012, the flowers became bigger, not smaller. Is this a strategy to keep attracting bees as they become less common?

Being an optimist I’m hoping that nature will adapt and figure out how to keep everybody happy.

Design trends

What’s New in the Garden in 2024

The flower buds, petals, young shoots and tubers of daylily are edible.

Gardening trends come & go. Who doesn’t love to read garden magazines with all those beautiful photographs during the winter and dream about your garden’s potential. Ditto for all the gardening blogs on the internet that are written by some very talented people who seem to have more free time than most of us. Here are some of the trends for 2024. You might already have incorporated some into your garden so pat yourself on the back and read on.

Like last year, enhancing your garden with edibles is again at the top of the list although now it’s got a fancy new name – Edimentals. Coined by writer Stephen Barstow of Norway edimentals are plants that are both edible and ornamental, therefore serving more than one function in the garden.

My friend Joy has foraged in her garden for years. You never know what’s going to be in one of her salads or soups. She would know that Pineapple Sage (Salvia elegans) is not only a fantastic fall-blooming perennial, but its scarlet flowers are great in salads, herbed cheeses and dressings.

Here are more reasons to add edimentals into your garden. Edimental plants are easy to care for. Perennials, shrubs and trees have fruiting times throughout the year rather than all at once. Their deeper roots make them hardier than annuals and better able to deal with drought or the occasional pest infestation. And when sprinkled throughout the entire garden, edimentals are a great way to draw kids out of the house and into the garden, encouraging them to forage while they wander. The flowers and tubers of both Dahlias and daylillies are examples of edimentals.

Another trend for 2024 isn’t really new. Naturalistic gardens consist mainly of native plants with drifts of flowers and grasses that look like a prairie that appears to have naturally re-seeded itself but in reality plants are carefully placed and chosen. The focus of a naturalistic garden is on a diversity of plants that blend with the surrounding nature and welcomes wildlife and pollinators. It’s neither manicured nor neglected. Sounds easy, doesn’t it?
Rethink that lawn this spring for a truly stunning yard.

Rain gardens are again trending. Around here it’s always a good idea to preserve runoff. Slow it, spread it, sink it should be our motto: catch the water, hold it on-site and get it back into the ground and out of storm drains. Roof and driveway pollutants from rain runoff are filtered by plant roots in a rain garden. Plants chosen for rain gardens need to handle the feast or famine amounts of water. Many native plants, grasses and sedges with their long, deep root structures.

The 4th trend for 2024 is learning to love bugs. While I can see that a few aphids, spider mites and whiteflies are not going to keep me up at night as long as the infestation isn’t too bad, I’m not sure about slugs and snails. The Royal Horticultural Society recently declassified slugs and snails as pests. The skunk and raccoon who frequent my garden will be happy to learn this. Me? Not so much.

Another trend is adapting and growing with a changing climate that is becoming hotter/colder, wetter, drier. Here are a few things you can do:
Choose the right plants that are more heat, cold, drought and pest resistant. Adjust your watering practices. Shift planting and harvesting dates and be prepared for extreme weather with row covers to protect from unexpected frost, shade cloth for excessive heat and materials for wind breaks.

Personally I embrace the smaller garden. You can create an instant meditation garden that encourages you to stop and sit for a couple minutes by placing a small bench where you can view something interesting in your garden. Small gardens are not only compact, they are easier to care for. Containers on the patio or deck allow you to grow plants for food as well as for the birds and the bees. There are more new dwarf vegetable, herb and flower varieties being introduced every year.

It’s always a good idea to remove overgrown shrubs and replace them with water smart, easy-to-care-for plants that will stay the right size in a smaller space. There are new compact and dwarf versions of old plants that have been garden favorites for a very long time. The reason they have endured is because they are reliable. Good reason to look again at some old favorites.


Everything old is new again.