Camellia flowers fall before they open

[axescot]

My camelia japonica bloomed many flowers but many have fallen before the flowers open. Is this normal?

 

[Marck]

What percentage of the total display would you estimate are are falling unopened? Any floriferous Camellia may drop some unopened buds, but if they are all dropping it could be a temperature or water issue.
More likely the latter in your climate. Could the plant's soil be too wet or too dry?

 

[cpp gardener]

Especially if it got dry in September/October when the buds were forming. It's the most critical time for blossom development.

 

[axescot]

I would say 40-50% of them are falling before completely opening. I water them about once per week but maybe that's not enough. I was kind of slacking off during that September/October time frame. I should also say it's only the largest one that's doing it. Maybe it's older or it needs more water because it's the largest.... I have it set up put a drip system with timer there. Just need to actually do it!

 

[Marck]

Irrigating once a week would be often enough for frequency, but be sure to irrigate deeply enough when you do so.

 

[cpp gardener]

If they are different varieties they will react differently. The key with drip systems is to run them for multiple hours instead of minutes. Their application rates are in gallons per hour, where regular spray heads are measured in gallons per minute - a 60fold difference.

 

[axescot]

If they are different varieties they will react differently. The key with drip systems is to run them for multiple hours instead of minutes. Their application rates are in gallons per hour, where regular spray heads are measured in gallons per minute - a 60fold difference.

Is there a website or other resource that you use to know how much water per day or per week for a particular plant?

 

[cpp gardener]

bewaterwise.com has a calculator for frequency and duration. Their standard application rate is 1G/minute for sprays and 1G/hour for drip/microspray. If you know the manufacturer of your system parts you can check their website. Consider Camellias a moderate water use plant. Their recommendation is to water once or twice a week. On our campus (Cal Poly Pomona) the standard schedule is 3 times a week, with varying duration depending on plant and exposure.

 

[Marck]

Two points to add.

Add a new layer of organic mulch now or at the beginning of the dry season. This can greatly conserve water by soil reducing soil evaporation. Only one of the many benefits of mulch.

Secondly always aim for making irrigation deeper and less frequent. It can take time for a plant to develop deeper roots, but the Camellia sound like they are established. Deeper roots can help any plant become more resilient to heat and drought.
Of course, there are limits depending on the species, climate and soil. However, I only water my in-ground Camellia once a week, in my very hot and dry summer climate.

 

[axescot]

bewaterwise.com has a calculator for frequency and duration. Their standard application rate is 1G/minute for sprays and 1G/hour for drip/microspray. If you know the manufacturer of your system parts you can check their website. Consider Camellias a moderate water use plant. Their recommendation is to water once or twice a week. On our campus (Cal Poly Pomona) the standard schedule is 3 times a week, with varying duration depending on plant and exposure.

I've seen bewaterwise.com before but it does not go into specifics about plants. For example, how much water to give a grape vine vs plum tree vs fig tree in summer, spring, winter, and fall. I read up on websites for those specific plants but nothing says this many gallons per week for this species in a particular season. Mostly what I hear is check the soil and to water deep. My yard is going to be full of 8 inch holes all over! Haha

 

[Marck]

Yes, observe the soil, temperature and other weather conditions, and the health and growth of the plants. You should only need to dig holes to get a baseline understanding of how water moves through your soil. Don't do it frequently or for every plant. It would be too laborious and you would damage their roots. Watering does become intuitive. You probably already have some intuition about it. As you irrigate you will begin to correlate plant growth with both water usage and the weather & season.

The WUCOLS database may also be helpful to you. It classifies most common garden plants into categories of water usage for six climatically similar regions in California. It is a good idea to try to group plants the same, water use category together.
There is a lot to read and process here.

https://ucanr.edu/sites/WUCOLS/

https://ucanr.edu/sites/scmg/files/30917.pdf