Brenda asks: I am very disappointed in my dragon fruit production this year. Although I did hand pollinate the flowers, most of them dropped off without producing fruit. What is the problem and what can I do to insure success
Brenda asks: I am very disappointed in my dragon fruit production this year. Although I did hand pollinate the flowers, most of them dropped off without producing fruit. What is the problem and what can I do to insure success in the future?
Tropical Gardener Answer: Dragon fruit, also known as pitaya or night-blooming cereus, is a native of Latin America and is now cultivated in many tropical and subtropical locations, including Hawaii. Dragon fruit are in the Hylocereeae genus and are members of the cactus family. Like other cactus, they are somewhat drought tolerant and have tough looking spiny stems, but they are actually somewhat sensitive and have several important requirements to produce a good crop of fruit.
The annual rainfall requirement for dragon fruit is 25-50 inches but excessive rain during flowering may cause flower drop. We did have lots of heavy rains this summer which may have adversely affected your flowers. Careful water management is essential to good production.
Pitaya are climbing cactuses that grow best with some support in a warm, humid climate with rich, organic soil. The flower buds will not survive extremely high temperatures over 100 degrees or intense sunlight. Under normal conditions, mature flowers will start opening around sunset and will be completely open by 10 p.m. The pollinated flowers will begin to wilt around 2 a.m. and be closed by dawn. Here in Hawaii we usually rely on hand pollination to insure good fruiting. On warm cloudy days flowers may open earlier and cool temperatures can slow down the wilting process. For best results, hand pollinate between 8-10 p.m. and check for wilting in the morning.
Dragon fruit’s root system is close to the soil’s surface and quickly absorbs nutrition and water. Good fruit production relies heavily on soil fertility and requires frequent fertilization. Applying about a standard balanced fertilizer to new plants after about three months will get the plants off to a good start. Adding well composted cow or steer manure in the root zone (but away from the stem) every quarter will also help with flowering and fruit production.
If you follow these guidelines, you will probably experience improved flower retention and fruit development.
Judy asks: I have some native pili grass growing in my yard and would like to plant more and expand my native Hawaiian garden. Can I propagate from what I have?
Tropical Gardener Answer: Pili grass is an attractive native Hawaiian plant with few pest problems. Propagating from your plants is a good idea as they usually only last for five years. Pili grass can be propagated by division or from seed.
To divide a clump, use a sharp spade or knife to cut off at least a square inch of the plant and its roots. Put the clump into a pot with a good fertile planting mix that drains well. In a few months, the plant should be strong enough to plant in your garden.
Once you see seed heads forming on your pili grass you can collect them once they are dry. Wear gloves and put the seeds in a plastic bag as they have very sharp tips that can pierce thin plastic and hurt your skin. Leave some seed heads on the plant to allow for some self-seeding. Pili seeds require a dormancy period before planting. Store packaged seeds for at least three months or more than a year in a cool dry place. Pre-soak the seeds overnight in water with a drop of liquid smoke added just before germination.
After soaking, lay the seeds on a mix of one part potting mix to three parts perlite. The seeds have sharp spikes with a twisted tail. Wet the seeded mix thoroughly with a spray bottle filled with 16 ounces of water to one drop of liquid smoke. In this moist environment, the seed tails straighten and drill the seed into the soil. Keep the medium moist (not wet) until you see germination which should occur within a month of planting.
Pili grass is a hearty ground cover that grows best in full to partial sun in soil that drains well. It is a drought tolerant plant that can tolerate wind, salt spray and high heat. It needs very little fertilizer and requires almost no attention. You can encourage new growth by weed whacking the tops periodically.
Diana Duff is a plant adviser, educator and consultant living on an organic farm in Captain Cook. Email plant questions to konamg@ctahr.hawaii.edu for answers by Certified Master Gardeners. Some questions will be chosen for inclusion in this column.
Gardening Events
Farmer Direct Markets
Wednesday: “Hooulu Farmers Market” 9 a.m. to 2 p.m. at Sheraton Kona Resort &Spa at Keauhou Bay
Wednesday: “Sunset Farmers Market” 2 p.m. to sunset at the north makai corner of the Kmart parking lot.
Saturday: “Keauhou Farmers Market” 8 a.m. to noon at Keauhou Shopping Center
“Kamuela Farmer’s Market” from 7 a.m. to noon at Pukalani Stables
Sunday: “South Kona Green Market” 9 a.m. – 2 p.m. at Amy Greenwell Garden in Captain Cook
Tuesday–Saturday: “U-Pick greens and produce” 10 a.m. to 4 p.m. Tropical Edibles Nursery, Captain Cook.
Plant Advice Lines
Anytime: konamg@ctahr.hawaii.edu
Tuesdays &Thursdays: 9 a.m. to noon at UH-CES in Kainaliu – 322-4892
Mondays, Tuesdays and Fridays: 9 a.m. to noon at UH CES at Komohana in Hilo 981-5199 or himga@hawaii.edu
