Q: My Mexican bird of paradise was gorgeous this year, the best ever. The flowers are now going to seed pods. Should I cut it back? What is the proper way to care for this plant as it moves into fall and winter?
A: The Mexican bird of paradise plant name is used by homeowners to describe two different but similar plants. They look similar except for the color of the flowers. The one with all yellow flowers, true Mexican bird of paradise, is more cold hardy than its cousin and native to south Texas and northern Mexico all the way to Sinaloa.
The other bird of paradise is more beautiful and has combined red, orange and yellow flowers. This red-flowered shrub is subtropical and can be found in the Caribbean, the South Pacific, including Hawaii, and all over tropical Asia.
It freezes to the ground in our climate when temperatures dip into the mid-20s. In the spring it regrows again and flowers. For these reasons we call it in our climate a “herbaceous perennial.” Trees and shrubs are “woody perennials.”
There is no right way or wrong way to prune or manage this plant except don’t let anyone prune it into a gumball. If the plant looks good and you like it, leave it alone. Remove some of the largest stems near the soil level every three or four years and let it regrow from the base.
If it’s getting too tall, cut the stems back to a foot or foot and a half above the ground early next February and let it regrow. Each cut will make two or three new stems that will grow shorter and slower than the single original stem. The plant will be denser with more flowers. With this kind of pruning, it will not look as natural as it would if you just left alone.
Fertilize it with a rose type fertilizer in February and lightly water it. If you don’t like the seed pods then remove them. It won’t hurt the plant.
Prune in January or February. Prune it if you don’t like its size, shape or density or prune two or three of the largest stems at the base every three to four years if you love everything about it.
Q: Can you please tell me if it is possible or not to use volcanic rock dust on a Venus fly trap to promote its growth?
A: Rock dust is a marketing term that means a very finely ground powder from different sources that contains dozens of minerals in small quantities. It is thought that soils that are used for a very long time become depleted of some minerals that cannot be replaced with fertilizers. Recently, this term has become a hot topic among gardeners on social media such as on YouTube and some gardening internet blogs.
I became interested in it because I was getting questions regarding its use. I experimented with three different kinds of rock dust and compared them for one growing season in some raised vegetable beds. All of the raised beds were composted, as they would be normally at the start of a growing season.
Perhaps it promotes growth in soils that do not have enough nutrients, but I did not test that. I have not seen any advantages to vegetable growth when it is applied to raised beds and the soil has been composted and amended correctly.
It does not hurt anything to apply it in small quantities, and it can be inexpensive insurance if you want to be sure. You don’t need much.
Venus fly trap grows in very poor soils. It gets its nutrients primarily from the soil when it can get it. Alternatively, it also takes nutrients from small insects that walk or fly into its trap. It evolved this way because of the poor soils. But catching insects and devouring them is an alternative to getting nutrients from the soil or leaves.
Regardless, the soil must drain well when growing these plants. Lava rock, perlite or pumice will help in that regard. They like high humidity so growing them in an enclosed terrarium will help.
Adding rock dust to the soil will not hurt it. But help it? Perhaps if the soil is lacking in any of the plant nutrients found in the rock dust.
Personally, I would use liquid fertilizer sprayed on the foliage much like you would orchids. This plant would like very much compost tea applied this way. They do not like rich, wet soils.
Q: This past November my next door neighbor’s African sumac trees were pruned to a trunk and branches. They were cut back so much I was sure they were being removed but was told they would leaf again. They did and are green and a lovely, smaller shape. I am planning to take the plunge with my tree but was advised to wait until February to avoid freezing damage. What should I do?
A: I will get to the February pruning. There is a right way and wrong way to radically prune large trees to a much smaller size. African sumac trees will survive this kind of pruning and you can get a much smaller tree.
But the resulting growth from this tree will be weakly attached to the main trunk and large branches. This results in a lot of future wind damage to the tree and it will cost more money to have this repaired later.
Radical pruning that dramatically reduces the size of a tree must always be done during the winter months. Winter freezing damage to this tree does not happen very often here so I am not overly concerned about waiting until February. Not a bad idea though if the tree will look ugly until it regrows.
We are talking about African sumac now. This type of pruning will not work on all large trees. If this type of pruning had been done to most ash trees, it would’ve killed them.
The acceptable method for reducing the size of larger trees is a technique called “drop crotching.” This technique identifies the tallest limbs and removes them at a crotch in the tree, using a clean cut that leaves no stubs. When cutting trees in this way, the height is reduced but strong limbs remain to support the canopy and reduce future wind damage.
Basically, drop crotching can be done to any large tree, not just African sumac. The type of pruning you saw done to your neighbor’s trees only works on trees that sucker easily from larger limbs.
Dramatically reducing the size of trees by pruning is best left to tree care professionals, certified arborists, who have passed rigorous exams demonstrating that they understand and can practice highly specialized form of pruning correctly. They are more expensive but they know how to do it correctly.
Q: I have a 12-year-old Chinaberry and I am trying to decide whether to keep it or not. I enjoy it in the spring because of its showy flowers but it has some dieback in the limbs and I fear it could be sooty canker disease. If it is sooty canker disease, is it necessary to remove immediately or could I keep it for at least one more spring? If so, should the affected limbs be removed now?
A: Sooty canker disease attacks many different types of trees and large shrubs including fruit trees. It causes limbs to die. If it spreads into the trunk, the tree should be removed. If it is only in the limbs, the infected limbs can be removed and the tree saved.
Yes, you could prune now with no problems. But you could wait a few months as it does not spread quickly.
This disease is easy to identify because dead limbs have bark that easily pulls from the wood. On the wood, under the bark, will be a black, sooty dust that looks just like soot from a chimney. It easily comes off on your fingers when you rub it, just like a sooty chimney. Spreading this soot is one way this disease can infect other trees.
Regardless, the tree needs to be pruned to remove dead limbs. Once the dead limbs are down, it may be easier to see if it is sooty canker disease. When pruning, make sure the saw is sanitized between cuts with diluted bleach or Pine Sol.
If the dead limbs are only infecting the branches, it is possible to save the tree by removing them. Be very careful to sanitize any equipment that comes in contact with infected plant parts.
Sooty canker usually attacks unhealthy trees. Make sure the tree is receiving enough water and receives a single fertilizer application each year in early spring.
Bob Morris is a horticulture expert living in Las Vegas and professor emeritus at the University of Nevada. Visit his blog at xtremehorticulture.blogspot.com. Send questions to Extremehort@aol.com.