San Francisco Gardening Information









 

 

Drought in California

2014 find us facing severe drought. Clearly gardening in San Francisco will have to change due to water restrictions. Composting helps to save water. Consider install drip a drip irrigation system to help save water. A grey water system to help to recycle household water for the garden is not yet cost efficient. I hope that companies will begin to work on bring down the price so more people could afford a grey water system. Lawns can be replaced with decorative rocks or wood clips, which take no water instead of even a low water ground cover plant, which does require some water. It is important not to forgot to water the trees on ones landscape in this time of drought. Many of the trees in San Francisco look unhealthy right now. Creating a tropical garden in San Francisco that has the look of a Florida Garden may be now completely impractical. I still have the information on Tropical Gardening posted below. I am updating with new information about the drought.

Growing Tips for Tropical Plants in colder climates

A Tropicalesque Garden is a garden that has tropical plants in a colder zone. We do not get summer heat. The summer fog creates cool damp conditions. Tropical Gardens grow best in Florida and Hawaii, but there are some tropical plants you can grow in San Francisco. San Francisco can support tropical plants such as palm trees, fan palms, banana leaf plants, bamboo, ferns, orchids, cannas, gingers, and elephants ears. The key to growing tropical plants in San Francisco is to plant in the early spring after the last cold day and give them time to become established before the cold weather comes in winter. If you are shopping in a nursery buy a the largest tropical plants you can afford. Larger plants are more likely to survive a cold spell. Also plant in a sheltered location if possible. Plants placed next to a house are kept warm by the house. Even planting next to a fence or under a tree is safer then out in the open. Cover your plants with sheets if cold weather is on the way, and water them well to help protect them from cold. Considering bring tropical plants indoors for the winter, or realize that your plant may only last a few seasons. Some San Francisco winters do not get as cold as other parts of the Bay Area. During a mild winter, your tropical will have more of a chance to become more established, before a colder winter hits. Look around San Francisco and notice what kind of tropical plants are growing as front landscaping. Those plants which are successful in San Francisco provide a starting point, but don't be afraid to experiment which a plant you have not seen growing in San Francisco. Use the web as a resource to find growing tips for the plants you have selected. Many of these plants need to be moved inside for the winter. Some can do well in a green house. Some of more cold hardy then others. Among orchids for example some varieties are more cold tolerant. If you want your plants to do well research carefully before you buy.

 

San Francisco Microclimates

San Francisco has three microclimates. One is more sunny such as the Castro and Noe Valley Neighborhoods which are east of Twin Peaks. The other microclimate is west of Twin Peaks near Ocean Beach or to the North near Baker Beach and the Golden Gate Bridge. Some San Francisco neighborhoods such as Glen Park are in a transitional zone in which has less fog then the fog zone, but not as much sun as the sun zone. Although there are even more microclimates in San Francisco, I will simplify by dividing them into sunny, foggy, and transition. These microclimates create special challenges for the San Francisco Gardener.

San Francisco Gardening Challenges

The lack of summer heat and the cold summer fog make vegetable gardening difficult in San Francisco. The damp cool conditions can cause fungal diseases such as powdery mildew, black spot, rust, and more. Some fruit trees need heat to cause the fruit to ripen properly. Be sure to research what edible plants work best in San Francisco. Meyer Lemon trees are a popular choice. California native plants do not grow as well in San Francisco as the warmer part of the Bay Area. California natives do not like amended soil, reclaimed water or drip irrigation. When growing California Natives it is critical that you remove all the weeds which compete with the desirable plants. The worse San Francisco weeds are weedy grasses like poa annua, oxalis, and dandelions. Some grass grow from runner roots and can come up into your yard from under a fence. Bindweed or wild morning glory and blackberries are particular troublesome plants that extent their roots under fences. Ivy can come from another yard, and once established can be difficult and costly to remove. Some trees in San Francisco can even appear in your garden as a weed. Once they have grown into a tree removable can be difficult. It is best to keep a vigilant eye upon garden weeds, and not let them spread out of control. Once weeds create seeds, it may take years to be rid of them. San Francisco has a large population of non native snails that will eat and multiple very quickly when left unchecked. Aphids can attack the new growth on plants such as roses and camellias. Often ants colonize aphids for the sweet honeydew. The water supply in San Francisco is alkaline and so is the soil. San Francisco Gardeners need to create more acid conditions by adding compost or other methods which shall not be discussed here. Most garden plant like slightly acid soil. Some plants like blueberries like very acid soil. I have found all my plants are improve by working to make my soil more acid.

Growing Roses in San Francisco

Hybrid teas are good roses for San Francisco. When choosing a hybrid tea select a rose that does not have too many flower petals. When conditions are damp the rose flower may not open all the way. This condition causes the flower to create a ball that never fully opens and instead rots. Heat will cause the rose to open fully. Select roses that are most resistant to fungal disease when choosing for San Francisco. Roses that will produce strong thick canes instead of spindly weak canes even in cool and foggy conditions are the best roses for San Francisco. The San Francisco Rose society has a list of rose recommendations available. Floribunda roses are good for San Francisco, but their flowers are smaller than hybrid teas. Landscape Roses or shrub roses are used in mass planting and have no advantage in resistance to fungal diseases. Miniature roses are not a good choice for San Francisco. Miniature roses are more subject to fungal diseases and need colder winters. Hybrid Rugosa Roses are subject to powdery mildew and will not grow well in San Francisco. The best rose for San Francisco is the one with the most resistance to fungal disease. Never plant your San Francisco roses in the shade or even part shade. San Francisco roses must have full sun. Do not get the leaves wet to minimize fungal diseases. It is best to water in the morning so any water on the leaves will dry quickly. Do not plant your roses in a location where they will be hit by sprinklers or ever water your roses using over head watering. Always water your rose from underneath.

Growing Poppies in San Francisco

Poppies are easy to grow in San Francisco, but you must plant them from seed. They do not transplant well. Poppies like a well drained sandy soil, but if you plant your seeds in a soil that is unamended and too hard, the roots will not go down far enough for the plant to be well rooted. This means the plant can be easily knocked over or blown down by wind. Once uprooted it is not possible to successfully replant the poppy. Plant your poppy seeds in the spring. If you plant them in the wrong season when the flowering time occurs the weather may not be warm enough to give you successful flowers. Save the seeds from the flower heads to plant again next spring. If the weather is not warm enough or a fungal diseases occurs the seeds may not be healthy enough to be viable next year. Keep the seeds as dry and possible. Allow them to air dry before storage. Poppies are water saving plants, do not over water them. Too much water, not enough heat or too rich a soil, will flavor the production of leaves instead of flowers.

Growing Hydrangeas in San Francisco

Hydrangea like San Francisco conditions and can be planted in full sun areas, but will also do well in half sun. Full shade will mean growth is stunned and less flowering. Hydrangeas like lots of water, and a rich compost soil. Unfortunately, hydrangeas are subject to fungal diseases of the leaves in San Francisco. A hydrangea can die from a fungal disease if the leaves are compromised to the point in which the plant is unable to manufacture energy from the sun. I suggest removing dead flower heads. If not the plant will not proceed as many nice new flowers. Neglected hydrangea clogged in weeds and under watered will survive in San Francisco, but will not be attractive. If the stems become thin weak the flower heads may sag, especially on Annabelle types. The quality standard for hydrangeas is the same as roses. Thick stems and healthy disease free leaves. Hydrangea macrophylla (mop heads) will only bloom on 2nd year wood, but some newer hybrids such as Endless Summer will bloom on new wood. Prune your hydrangea after flowering. Make your pruning decisions based on whether your hydrangea blooms on old or new wood. Some hydrangeas will bloom on both old and new wood, and some will only bloom on new growth. Hydrangeas are high water plants. They are not good for drought conditions. Composting can help a great deal in saving water. Once compost is applied to soil it helps to hold in water in the soil. But, it will prudent to move away from Hydrangea Garden in the future.

Growing Tulips in San Francisco

 Tulips can be successful, but you should plant them in late February, and it is helpful to keep them refrigerated from December until planting time without any fruits such as apples which give off a harmful gas. Tulips will probably not rebloom in San Francisco. You can try digging them up every year and refrigerating them again, but many warm climate gardeners treat tulips as annuals and buy fresh bulbs each year. Tulips have a deeper plant depth than most other bulbs, but this does not apply to San Francisco because the ground won't freeze. You can plant them just two inches below the surface to make them easier to dig up in the spring. You can buy tulips online, but major growers only large sets of bulbs such as sets of 50 or 100 bulbs. This may be overwhelming for a smaller San Francisco Garden. Most San Francisco Gardens are small. You can also buy tulip bulbs from a garden center or retail giant such as Wal-Mart or Home Depot. Only select large firm bulbs without any black spots.  Tulips recommended for San Francisco include Queen of the Night, and Apricot Beauty. There are other types of tulips bulbs that are smaller with shorter stems such as Tulipa greigii that can grow well in San Francisco.

Growing Bulbs in San Francisco

 Calla lilies are very hardly in San Francisco, but the white ones may become invasive. The colored calla hybrids do will in San Francisco, but they like a rich soil and plenty of water. If they do not get enough sun, they will tend to mostly leaves without flowers. You may need to experiment to see which bulbs come back year after year in San Francisco. If the bulb refuses to sprout it may be that it got too much moisture over the winter and rotted in the ground. Begonias will do well with an eastern exposure. Begonias are delicate plants and like to be sheltered so plant in front of a house or a garden wall.  Daffodils and their smaller cousins Narcissus will do will in San Francisco and will rebloom. Day lilies, bearded irises and gladiolus can be successfully grown in San Francisco. Trout lilies and lily of the valley are good shade bulbs, but they need a lot of water and soil rich in compost.  Most bulbs are better off if left in the ground over the winter, due to the fact they are subject to shriveling and rotting in storage. But, if the winter is wet, the bulbs may rot anyway, so hopefully you have improved your soil to increase drainage.

Growing Annuals in San Francisco

Pansies and violas do well in Francisco. These are annuals that do not require summer heat to bloom well. These annuals may last for more than one year in San Francisco, but they can lose vigor over time. Many other annuals do well in San Francisco such as stock, snap dragons, and daisies. Fox Gloves and primroses are biennial plants. They last for two years. Sometimes fox gloves only bloom the second year. However, stress can speed up the time it takes a fox glove to begin to flower.

Growing Perennials Vines in San Francisco

Perennials come back year after year. Perennials do well in San Francisco. I have done very well with Clematis 'Nelly Moser'. Clematis need very good drainage. If you buy a clematis and the roots appear to be unhealthy, this is caused by poor drainage in a pot. It can be difficult to establish a clematis, but once established are hardly plants. Jasmine Vines are a popular choice. Pink Jasmine which has white flowers may become invasive in San Francisco. Yellow Jasmine is not as hardly as Pink Jasmine. Star Jasmine can be a vine or a ground cover. Black Eyed Susan Vine comes in yellow or orange flowers. Sweet peas are annual vines, but there are perennial sweet peas available. Sweet Peas are subject to powdery mildew. Although some sweet peas don't like heat, they do not do as well as one might hope in San Francisco. The vines can become too thick and the flowers can be small. Wall Flowers have even smaller flowers then sweet peas, but can be charming. I have grown a red wall flower from seed. Nasturtiums do very well, and can become a weed. If the soil is rich they will go to leaves, and not have as many flowers. When growing in wild conditions with little water and a sandy soil nasturtiums will give the best display.

Growing Vegetables in San Francisco

Zucchini, curly leaf parsley, lettuce, broccoli, beets, carrots, and radishes will do great even in the foggiest parts of the city. Tomatoes, corn, basil and peppers will do much better in the sunnier microclimates. Strawberries will do ok, but would be better if they got more heat. One tip is to buy the biggest plant possible instead of growing from seed because you are more likely to get some kind of harvest. I have grown cucumber and pumpkins and did not get good results, but many pumpkins are grown in near by Half Moon Bay. Since conditions vary from year to year, one year you may have a suggest with some types of crops and another year they may fail. Mint does well in San Francisco, but should only be grown in pots because it is invasive.

Growing Rhododendrons, azaleas and camellias in San Francisco

Rhododendrons and camellias do well in San Francisco in half shade or dappled shade. A lack of sun light can cause slow growth, and algae may begin to grow on the leaves. I have found a product called Physan 20 which kills the algae on the leaves of Rhododendrons and camellias. Rhododendrons, azaleas and camellias all like an acid well drained soil. San Francisco water is very alkaline so you may want to use a soil acidifier. Rhododendrons and camellias can grow very large. I have a dwarf camellia called Nuccio's Pearl which is a pink flower. Nuccio's Gem is a white flowered Camilla. I think the pearl should be white, but one must think of the flower as a pink pearl. I have a pink miniature Rhododendron that I bought from the Rhododendron Society at a local sale at Lake Merritt. I also have one large Rhododendron called Pink Lady. The flowers on Pink Lady start out as purple, but fade to pink. One tip is they do not like their root zone to be crowded with other smaller plants, because their root zone is very shallow. Damage to the roots by digging around could hurt the over all health of the plant.

Shade Gardening in San Francisco

Ferns and tree ferns do well in San Francisco. Woodwardia Orientalis and Woodwardia orientalis var. formosana are lovely ferns you can grow in San Francisco, but they may need a green house. These Oriental Chain Fern species do not like temperatures below 50 degrees. Woodwardia fimbriata is native to California, and will do very well in San Francisco. This is a big bushy plant that can grow huge heights, and does not mine the cold weather in San Francisco. Woodwardia virginica is native to Virginia. I would like to try growing one someday. I am growing the autumn fern, the lady fern, and another common sword fern type. But, I found this sword fern that came as a volunteer to be susceptible to infestations of tiny white aphids and also to black smut fungal diseases Oxalis hybrids are not invasive and can grow in shade or sun in San Francisco. I am growing the white Oxalis with big green leaves and white flowers and the Purple leaf variety. The Purple leaf Oxalis (Oxalis regnellii 'Atropurpurea') gets a lot of rust. Viola labradorica pursuer (true violets) will accept dry shade, but may become invasive. Viola tricolor or Johnny Jump up will grown in shade or sun, but reseed themselves and may become weed if not managed. Begonias, trout lilies, and lily of valley are good shade bulbs, but would like some sun for better blooming. They like a rich soil and to watered in the afternoon. Impatiens are good shade choices with colorful flowers. Fuchsias are good for San Francisco, but will die in the winter unless they are well established with woody growth.Botrytis Blight killed off a large number of fuchsias in San Francisco.It can only be helped by using Daconil. Clivia miniata also called a Kaffir Lily is a good plant for San Francisco. Golden Gate Park has a lot of them because they are easy care. The thick strap like leaves are subject to freezing and cold damage when the temperatures get low, but they will rebound the next year. Clivia comes in shades of red, orange, yellow and occasionally pinks and reds can be found. Hostas are shade plants, but will take more sun in San Francisco.

Growing Hostas in San Francisco

Not all hostas will grow well in San Francisco. Some hostas need cold winters in which they go dormant and come back stronger the following year. Local nurseries stock hostas that are proven to emerge from dormancy in the spring despise our mild winters. Hostas prefer a sandy or clay soil with lots of organic compost added. They like part shade. They would prefer morning sun and afternoon shade. They like plentiful watering in the dry months. If you stop watering your hosta for more then two weeks, and there is no rain, it may begin to go dormant or die and may not come back the next year. Yellow hostas are the most difficult hostas to grow. The easiest hostas are all green, followed by blue hostas. Blue hostas start out green, but then build a blue colored wax that makes them look book late in the season. Hosta with strips are more likely to suffer from a hosta virus. If you want to try and easy hosta try one that is all green and a medium size as the smaller and larger varieties may be more temperamental. If you look online you can find lists of hostas recommendations for climates that do not have a cold winter. Hostas like a lot of water, so it may be wise to begin to grow Heuchera (coral bells) instead of Hostas has they like shade, but take less water.

I hope I helped you with your San Francisco Gardening. Feel free to ask me a question if you have one.

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