Bulbs produce some of the most beautiful flowers in the garden palate. They can provide brilliant splashes of cheerful color in the winter and spring months.
In Arizona, bulbs can be grown in the landscape, in containers on the patio, or even indoors. Indeed, many native Arizona plants are bulbs.
Technically, a bulb is just a type of underground storage organ, composed of swollen, fleshy leaves, like an onion. Plants have also invented underground storage organs based on stems, including rhizomes, tubers and corms. For ease of discussion, I will call all of these “bulbs” in this article.
• Get the right stuff. In general, bulbs with hot climate ancestors will do better than their European cousins. Thus, such desert tulips as Turkish or Israeli tulips will do better than Dutch tulips. Dutch bulbs have been bred for the past five centuries to thrive in cold, wet climates.
• Plant it right. Not all sun is created equal. In Arizona, our sun can heat and dry the soils in excess of what is appropriate for many bulbs. This is one of the few cases where you should ignore the label if you want your bulbs to reappear every year.
• Full shade to filtered shade in summer is needed for the following bulbs to grow well here: agapanthus, caladium, calla, canna, crinum, crocus, cyclamen, dahlia, day lily, Easter lily, freesia, gladiolus, lycoris, ornithogalum, oxalis, sparaxis, spring starflower (Ipheion), tigridia, and tuberous begonia. All prefer less than full summer sun in our growing conditions. Especially avoid the baking afternoon sun.
• Full sun to part shade is needed for the following bulbs (Our natives are marked by an asterisk*): Ajo lily*, allium, amaryllis, anemone, apios, blue dicks*, canna, crocus, gladiolus, iris (all kinds), mariposa lily*, narcissus, oxalis, Pima lily*, ranunculus, society garlic, squill, Turkish tulip, watsonia, zephranthes. Some plants are listed on both lists; this means they will stand about half a day of summer sun.
• Plant it now. You can plant bulbs all year long in the Old Pueblo. Ideally, the sooner dormant bulbs are out of their shipping packages and into the soil, the better.
• Drain it right. Proper drainage is absolutely essential for bulbs. Sandy soils are ideal, but if your soil is more clay, amend the soil. To amend, simply mix in organic matter such as compost or peat moss, plus perlite or sand will help, too. Amending the soil is the hardest part of growing anything in our area, but once you have loosened the soil the first time, planting anything will be easier. Amending the soil also improves the area for later planting of other colorful plants.
• Plant it right. Planting depth is important to bulbs. If your bulbs don’t come with instructions, the best rule of thumb is that the bulb should be planted two to three times as deep as it is tall. Thus a 2-inch bulb (from rootlets to pointy tip) should be planted with the growing tip 4 to 6 inches below the top of the soil. This depth also helps discourage critters from finding them.
• Water it right. Allow the soil to dry fairly well between waterings, but not bone dry. Drying allows oxygen to filter into the soil, and the bulbs need plenty of oxygen for emerging from the bulb and flowering. Once bulbs show green leaves, keep the soil a little more moist. They will reward the extra attention with a longer season of flowering.
• General care. Virtually all of the bulbs listed will survive in the ground all year long (especially if the drainage is good). Dahlia and ranunculus are the exceptions. They really do not take the heat of summer, and do better if dug up and stored in a cool, dry place for planting next fall. Anenome is another problem child. They may survive if your material is from the hot dry areas of either Greece or Texas.
• Containers of bulbs. Containers and bulbs go well together and can really spruce up the patio. Large or small containers are fine. Just be sure that drainage holes are adequate, and don’t block them. Potting soil should be mixed with perlite or vermiculite and sand, or a cactus mix will do well. Planting depth is the same. Water should be thorough, and some should come out the bottom drain of the pot. Do allow the soil to dry between watering to allow good aeration.
• As always, enjoy!
Soule’s book, “Father Kino’s Herbs: Growing and Using Them Today,” is available at area nurseries.